FAM111B Mutation Is Associated With Inherited Exocrine Pancreatic Dysfunction.

Pancreas. 2016 07;45(6):858-62

Authors: Seo A, Walsh T, Lee MK, Ho PA, Hsu EK, Sidbury R, King MC, Shimamura A

Abstract
OBJECTIVES: Few genetic causes of exocrine pancreatic dysfunction have been described to date. We identified a family with multiple affected members manifesting exocrine pancreatic dysfunction. Additional associated features included facial rash, sparse hair, hypohidrosis, and swelling of the extremities. The transmission pattern of these clinical features was consistent with an autosomal dominant mode of inheritance. The 2 proband siblings also had transient elevated liver transaminases with hepatic steatosis early in life. This study identifies the genetic cause of exocrine pancreatic dysfunction in this family.
METHODS: Whole exome sequencing was performed to identify the genetic cause of exocrine pancreatic dysfunction.
RESULTS: A heterozygous germline in-frame deletion in the gene FAM111B (c.1261_1263delAAG, p.Lys421del) cosegregated with the phenotype: the variant was present in all affected relatives genotyped and absent in all unaffected relatives genotyped. The variant is also absent from public control sequence databases.
CONCLUSIONS: Our findings implicate FAM111B in autosomal dominantly inheritable exocrine pancreatic dysfunction.

PMID: 26495788 [PubMed - indexed for MEDLINE]

Abnormal glycosylation in Joubert syndrome type 10.

Cilia. 2017;6:2

Authors: Kane MS, Davids M, Bond MR, Adams CJ, Grout ME, Phelps IG, O'Day DR, Dempsey JC, Li X, Golas G, Vezina G, Gunay-Aygun M, Hanover JA, Doherty D, He M, Malicdan MC, Gahl WA, Boerkoel CF

Abstract
BACKGROUND: The discovery of disease pathogenesis requires systematic agnostic screening of multiple homeostatic processes that may become deregulated. We illustrate this principle in the evaluation and diagnosis of a 5-year-old boy with Joubert syndrome type 10 (JBTS10). He carried the OFD1 mutation p.Gln886Lysfs*2 (NM_003611.2: c.2656del) and manifested features of Joubert syndrome.
METHODS: We integrated exome sequencing, MALDI-TOF mass spectrometry analyses of plasma and cultured dermal fibroblasts glycomes, and full clinical evaluation of the proband. Analyses of cilia formation and lectin staining were performed by immunofluorescence. Measurement of cellular nucleotide sugar levels was performed with high-performance anion-exchange chromatography with pulsed amperometric detection. Statistical analyses utilized the Student's and Fisher's exact t tests.
RESULTS: Glycome analyses of plasma and cultured dermal fibroblasts identified abnormal N- and O-linked glycosylation profiles. These findings replicated in two unrelated males with OFD1 mutations. Cultured fibroblasts from affected individuals had a defect in ciliogenesis. The proband's fibroblasts also had an abnormally elevated nuclear sialylation signature and increased total cellular levels of CMP-sialic acid. Ciliogenesis and each glycosylation anomaly were rescued by expression of wild-type OFD1.
CONCLUSIONS: The rescue of ciliogenesis and glycosylation upon reintroduction of WT OFD1 suggests that both contribute to the pathogenesis of JBTS10.

PMID: 28344780 [PubMed - in process]

Leveraging blood serotonin as an endophenotype to identify de novo and rare variants involved in autism.

Mol Autism. 2017;8:14

Authors: Chen R, Davis LK, Guter S, Wei Q, Jacob S, Potter MH, Cox NJ, Cook EH, Sutcliffe JS, Li B

Abstract
BACKGROUND: Autism spectrum disorder (ASD) is one of the most highly heritable neuropsychiatric disorders, but underlying molecular mechanisms are still unresolved due to extreme locus heterogeneity. Leveraging meaningful endophenotypes or biomarkers may be an effective strategy to reduce heterogeneity to identify novel ASD genes. Numerous lines of evidence suggest a link between hyperserotonemia, i.e., elevated serotonin (5-hydroxytryptamine or 5-HT) in whole blood, and ASD. However, the genetic determinants of blood 5-HT level and their relationship to ASD are largely unknown.
METHODS: In this study, pursuing the hypothesis that de novo variants (DNVs) and rare risk alleles acting in a recessive mode may play an important role in predisposition of hyperserotonemia in people with ASD, we carried out whole exome sequencing (WES) in 116 ASD parent-proband trios with most (107) probands having 5-HT measurements.
RESULTS: Combined with published ASD DNVs, we identified USP15 as having recurrent de novo loss of function mutations and discovered evidence supporting two other known genes with recurrent DNVs (FOXP1 and KDM5B). Genes harboring functional DNVs significantly overlap with functional/disease gene sets known to be involved in ASD etiology, including FMRP targets and synaptic formation and transcriptional regulation genes. We grouped the probands into High-5HT and Normal-5HT groups based on normalized serotonin levels, and used network-based gene set enrichment analysis (NGSEA) to identify novel hyperserotonemia-related ASD genes based on LoF and missense DNVs. We found enrichment in the High-5HT group for a gene network module (DAWN-1) previously implicated in ASD, and this points to the TGF-β pathway and cell junction processes. Through analysis of rare recessively acting variants (RAVs), we also found that rare compound heterozygotes (CHs) in the High-5HT group were enriched for loci in an ASD-associated gene set. Finally, we carried out rare variant group-wise transmission disequilibrium tests (gTDT) and observed significant association of rare variants in genes encoding a subset of the serotonin pathway with ASD.
CONCLUSIONS: Our study identified USP15 as a novel gene implicated in ASD based on recurrent DNVs. It also demonstrates the potential value of 5-HT as an effective endophenotype for gene discovery in ASD, and the effectiveness of this strategy needs to be further explored in studies of larger sample sizes.

PMID: 28344757 [PubMed - in process]

Identification of a novel DMD duplication identified by a combination of MLPA and targeted exome sequencing.

Mol Cytogenet. 2017;10:8

Authors: Wu B, Wang L, Dong T, Jin J, Lu Y, Wu H, Luo Y, Shan X

Abstract
BACKGROUND: Duchenne muscular dystrophy (DMD) is an X-linked recessive muscle-wasting disease caused by a mutation in the DMD gene. The aim of this study was to identify a de novo mutation of the DMD gene in the family of a 9-month-old Chinese male patient, as well as to describe the phenotypic characteristics of this patient.
RESULTS: The patient was suspected to suffer from DMD according to physical examination, biochemical analyses, and electromyogram. We identified a duplication of exons 4-42 in DMD gene with targeted exome sequencing and multiplex ligation-dependent probe amplification (MLPA). In addition, the patient's mother was a carrier of the same mutation.
CONCLUSIONS: We identified a de novo duplication of exons 4-42 in a patient with early stage DMD. The discovery of this mutation may provide insights into future investigations.

PMID: 28344651 [PubMed - in process]

Global developmental delay and intellectual disability associated with a de novo TOP2B mutation.

Clin Chim Acta. 2017 Mar 23;:

Authors: Lam CW, Yeung WL, Law CY

Abstract
BACKGROUND: More than 100 genes had been identified for autism spectrum disorder (ASD). With the advancement of whole-exome/genome sequencing (WES/WGS), disease-causing gene in ASD can be identified in a holistic and unbiased approach. The identification of new ASD genes can further explore the molecular basis of ASD.
METHODS: We report a 15yo girl with developmental delay, intellectual disability, hypotonia, microcephaly and autistic feature. She first presented at 6months old with primitive response to noise. Physical examination showed the patient was hypotonic despite normal muscle power and reflexes. She also had progressive microcephaly. Developmental assessment at 6y showed the patient had a corresponding functional age of 1y. The patient also had autistic feature.
RESULTS: The patient had no abnormal biochemical or radiological findings. To investigate the molecular basis of the clinical presentation, we applied clinical whole-exome sequencing (WES) for the proband and the family, and we identified a novel de novo heterozygous missense pathogenic variant, TOP2B: NM_001068.2:c.172C>T; NP_001059.2:p.His58Tyr. TOP2B encodes for the enzyme, topoisomerase II isoenzyme beta which is abundant in both developing and adult brain. Defect of topoisomerase is also known to cause ASD.
CONCLUSIONS: Using clinical WES, we were able to identify the disease-causing gene for this patient in a holistic approach and end the diagnostic odyssey with a therapeutic impact.

PMID: 28343847 [PubMed - as supplied by publisher]

Improved full-length killer cell immunoglobulin-like receptor transcript discovery in Mauritian cynomolgus macaques.

Immunogenetics. 2017 Mar 25;:

Authors: Prall TM, Graham ME, Karl JA, Wiseman RW, Ericsen AJ, Raveendran M, Alan Harris R, Muzny DM, Gibbs RA, Rogers J, O'Connor DH

Abstract
Killer cell immunoglobulin-like receptors (KIRs) modulate disease progression of pathogens including HIV, malaria, and hepatitis C. Cynomolgus and rhesus macaques are widely used as nonhuman primate models to study human pathogens, and so, considerable effort has been put into characterizing their KIR genetics. However, previous studies have relied on cDNA cloning and Sanger sequencing that lack the throughput of current sequencing platforms. In this study, we present a high throughput, full-length allele discovery method utilizing Pacific Biosciences circular consensus sequencing (CCS). We also describe a new approach to Macaque Exome Sequencing (MES) and the development of the Rhexome1.0, an adapted target capture reagent that includes macaque-specific capture probe sets. By using sequence reads generated by whole genome sequencing (WGS) and MES to inform primer design, we were able to increase the sensitivity of KIR allele discovery. We demonstrate this increased sensitivity by defining nine novel alleles within a cohort of Mauritian cynomolgus macaques (MCM), a geographically isolated population with restricted KIR genetics that was thought to be completely characterized. Finally, we describe an approach to genotyping KIRs directly from sequence reads generated using WGS/MES reads. The findings presented here expand our understanding of KIR genetics in MCM by associating new genes with all eight KIR haplotypes and demonstrating the existence of at least one KIR3DS gene associated with every haplotype.

PMID: 28343239 [PubMed - as supplied by publisher]

De novo mutations in CBL causing early-onset paediatric moyamoya angiopathy.

J Med Genet. 2017 Mar 25;:

Authors: Guey S, Grangeon L, Brunelle F, Bergametti F, Amiel J, Lyonnet S, Delaforge A, Arnould M, Desnous B, Bellesme C, Hervé D, Schwitalla JC, Kraemer M, Tournier-Lasserve E, Kossorotoff M

Abstract
BACKGROUND: Moyamoya angiopathy (MMA) is characterised by a progressive stenosis of the terminal part of the internal carotid arteries and the development of abnormal collateral deep vessels. Its pathophysiology is unknown. MMA can be the sole manifestation of the disease (moyamoya disease) or be associated with various conditions (moyamoya syndrome) including some Mendelian diseases. We aimed to investigate the genetic basis of moyamoya using a whole exome sequencing (WES) approach conducted in sporadic cases without any overt symptom suggestive of a known Mendelian moyamoya syndrome.
METHODS: A WES was performed in four unrelated early-onset moyamoya sporadic cases and their parents (trios). Exome data were analysed under dominant de novo, autosomal recessive and X-linked hypotheses. A panel of 17 additional sporadic cases with early-onset moyamoya was available for mutation recurrence analysis.
RESULTS: We identified two germline de novo mutations in CBL in two out of the four trio probands, two girls presenting with an infancy-onset severe MMA. Both mutations were predicted to alter the ubiquitin ligase activity of the CBL protein that acts as a negative regulator of the RAS pathway. These two germline CBL mutations have previously been described in association with a developmental Noonan-like syndrome and susceptibility to juvenile myelomonocytic leukaemia (JMML). Notably, the two mutated girls never developed JMML and presented only subtle signs of RASopathy that did not lead to evoke this diagnosis during follow-up.
CONCLUSIONS: These data suggest that CBL gene screening should be considered in early-onset moyamoya, even in the absence of obvious signs of RASopathy.

PMID: 28343148 [PubMed - as supplied by publisher]

A Low-Frequency Inactivating Akt2 Variant Enriched in the Finnish Population is Associated With Fasting Insulin Levels and Type 2 Diabetes Risk.

Diabetes. 2017 Mar 24;:

Authors: Manning A, Highland HM, Gasser J, Sim X, Tukiainen T, Fontanillas P, Grarup N, Rivas MA, Mahajan A, Locke AE, Cingolani P, Pers TH, Viñuela A, Brown AA, Wu Y, Flannick J, Fuchsberger C, Gamazon ER, Gaulton KJ, Im HK, Teslovich TM, Blackwell TW, Bork-Jensen J, Burtt NP, Chen Y, Green T, Hartl C, Kang HM, Kumar A, Ladenvall C, Ma C, Moutsianas L, Pearson RD, Perry JR, Rayner NW, Robertson NR, Scott LJ, van de Bunt M, Eriksson JG, Jula A, Koskinen S, Lehtimäki T, Palotie A, Raitakari OT, Jacobs SB, Wessel J, Chu AY, Scott RA, Goodarzi MO, Blancher C, Buck G, Buck D, Chines PS, Gabriel S, Gjesing AP, Groves CJ, Hollensted M, Huyghe JR, Jackson AU, Jun G, Justesen JM, Mangino M, Murphy J, Neville M, Onofrio R, Small KS, Stringham HM, Trakalo J, Banks E, Carey J, Carneiro MO, DePristo M, Farjoun Y, Fennell T, Goldstein JI, Grant G, Hrabé de Angelis M, Maguire J, Neale BM, Poplin R, Purcell S, Schwarzmayr T, Shakir K, Smith JD, Strom TM, Wieland T, Lindstrom J, Brandslund I, Christensen C, Surdulescu GL, Lakka TA, Doney AS, Nilsson P, Wareham NJ, Langenberg C, Varga TV, Franks PW, Rolandsson O, Rosengren AH, Farook VS, Thameem F, Puppala S, Kumar S, Lehman DM, Jenkinson CP, Curran JE, Hale DE, Fowler SP, Arya R, DeFronzo RA, Abboud HE, Syvänen AC, Hicks PJ, Palmer ND, Ng MC, Bowden DW, Freedman BI, Esko T, Mägi R, Milani L, Mihailov E, Metspalu A, Narisu N, Kinnunen L, Bonnycastle LL, Swift A, Pasko D, Wood AR, Fadista J, Pollin TI, Barzilai N, Atzmon G, Glaser B, Thorand B, Strauch K, Peters A, Roden M, Müller-Nurasyid M, Liang L, Kriebel J, Illig T, Grallert H, Gieger C, Meisinger C, Lannfelt L, Musani SK, Griswold M, Taylor HA, Wilson G, Correa A, Oksa H, Scott WR, Afzal U, Tan ST, Loh M, Chambers JC, Sehmi J, Kooner JS, Lehne B, Cho YS, Lee JY, Han BG, Käräjämäki A, Qi Q, Qi L, Huang J, Hu FB, Melander O, Orho-Melander M, Below JE, Aguilar D, Wong TY, Liu J, Khor CC, Chia KS, Lim WY, Cheng CY, Chan E, Tai ES, Aung T, Linneberg A, Isomaa B, Meitinger T, Tuomi T, Hakaste L, Kravic J, Jørgensen ME, Lauritzen T, Deloukas P, Stirrups KE, Owen KR, Farmer AJ, Frayling TM, O'Rahilly SP, Walker M, Levy JC, Hodgkiss D, Hattersley AT, Kuulasmaa T, Stančáková A, Barroso I, Bharadwaj D, Chan J, Chandak GR, Daly MJ, Donnelly PJ, Ebrahim SB, Elliott P, Fingerlin T, Froguel P, Hu C, Jia W, Ma RC, McVean G, Park T, Prabhakaran D, Sandhu M, Scott J, Sladek R, Tandon N, Teo YY, Zeggini E, Watanabe RM, Koistinen HA, Kesaniemi YA, Uusitupa M, Spector TD, Salomaa V, Rauramaa R, Palmer CN, Prokopenko I, Morris AD, Bergman RN, Collins FS, Lind L, Ingelsson E, Tuomilehto J, Karpe F, Groop L, Jørgensen T, Hansen T, Pedersen O, Kuusisto J, Abecasis G, Bell GI, Blangero J, Cox NJ, Duggirala R, Seielstad M, Wilson JG, Dupuis J, Ripatti S, Hanis CL, Florez JC, Mohlke KL, Meigs JB, Laakso M, Morris AP, Boehnke M, Altshuler D, McCarthy MI, Gloyn AL, Lindgren CM

Abstract
To identify novel coding association signals and facilitate characterization of mechanisms influencing glycemic traits and type 2 diabetes risk, we analyzed 109,215 variants derived from exome array genotyping together with an additional 390,225 variants from exome sequence in up to 39,339 normoglycemic individuals from five ancestry groups. We identified a novel association between the coding variant (p.Pro50Thr) in AKT2 and fasting insulin, a gene in which rare fully penetrant mutations are causal for monogenic glycemic disorders. The low-frequency allele is associated with a 12% increase in fasting plasma insulin (FI) levels. This variant is present at 1.1% frequency in Finns but virtually absent in individuals from other ancestries. Carriers of the FI-increasing allele had increased 2-hour insulin values, decreased insulin sensitivity, and increased risk of type 2 diabetes (odds ratio=1.05). In cellular studies, the AKT2-Thr50 protein exhibited a partial loss of function. We extend the allelic spectrum for coding variants in AKT2 associated with disorders of glucose homeostasis and demonstrate bidirectional effects of variants within the pleckstrin homology domain of AKT2.

PMID: 28341696 [PubMed - as supplied by publisher]

Molecular and Functional Characterization of Rare CACNA1C Variants in Sudden Unexplained Death in the Young.

Congenit Heart Dis. 2016 Dec;11(6):683-692

Authors: Sutphin BS, Boczek NJ, Barajas-Martínez H, Hu D, Ye D, Tester DJ, Antzelevitch C, Ackerman MJ

Abstract
INTRODUCTION: Perturbations in the CACNA1C-encoded L-type calcium channel α-subunit have been linked recently to heritable arrhythmia syndromes, including Timothy syndrome, Brugada syndrome, early repolarization syndrome, and long QT syndrome. These heritable arrhythmia syndromes may serve as a pathogenic basis for autopsy-negative sudden unexplained death in the young (SUDY). However, the contribution of CACNA1C mutations to SUDY is unknown.
OBJECTIVE: We set out to determine the spectrum, prevalence, and pathophysiology of rare CACNA1C variants in SUDY.
METHODS: Mutational analysis of CACNA1C was conducted in 82 SUDY cases using polymerase chain reaction, denaturing high-performance liquid chromatography, and direct sequencing. Identified variants were engineered using site-directed mutagenesis, and heterologously expressed in TSA-201 or HEK293 cells.
RESULTS: Two SUDY cases (2.4%) harbored functional variants in CACNA1C. The E850del and N2091S variants involve highly conserved residues and localize to the II-III linker and C-terminus, respectively. Although observed in publically available exome databases, both variants confer abnormal CaV 1.2 electrophysiological characteristics. Examination of the electrophysiological properties revealed the E850del mutation in CACNA1C led to a 95% loss-of-function in ICa , and the N2091S variant led to a 105% gain-of-function in ICa. Additionally, N2091S led to minor kinetic alterations including a -3.4 mV shift in V1/2 of activation.
CONCLUSION: This study provides molecular and functional evidence that rare CACNA1C genetic variants may contribute to the underlying pathogenic basis for some cases of SUDY in either a gain or loss-of-function mechanism.

PMID: 27218670 [PubMed - indexed for MEDLINE]

Next-generation sequencing of urine specimens: A novel platform for genomic analysis in patients with non-muscle-invasive urothelial carcinoma treated with bacille Calmette-Guérin.

Cancer. 2017 Mar 24;:

Authors: Scott SN, Ostrovnaya I, Lin CM, Bouvier N, Bochner BH, Iyer G, Solit D, Berger MF, Lin O

Abstract
BACKGROUND: Biopsies from patients with high-risk (HR) non-muscle-invasive urothelial carcinoma (NMIUC), especially flat urothelial carcinoma in situ, frequently contain scant diagnostic material or denuded mucosa only, and this precludes further extensive genomic analysis. This study evaluated the use of next-generation sequencing (NGS) analysis of urine cytology material from patients with HR NMIUC in an attempt to identify genetic alterations that might correlate with clinical features and responses to bacille Calmette-Guérin (BCG) treatment.
METHODS: Forty-one cytology slides from patients with HR NMIUC treated with intravesical BCG were selected for this study. Histological confirmation was available for all cases. The specimens were subjected to NGS analysis with a customized targeted exome capture assay composed of 341 genes.
RESULTS: In this cohort, genomic alterations were successfully identified in all cytology samples. Mutations were detected down to a 2% allele frequency and chromosomal rearrangements including copy number alterations and gene fusions were identified. The most frequently altered genes included telomerase reverse transcriptase (TERT), tumor protein 53 (TP53), Erb-B2 receptor tyrosine kinase 2 (ERBB2), and chromatin remodeling genes such as lysine demethylase 6A (KDM6A) and AT-rich interaction domain 1A (ARID1A). For patients with matched tumor tissue, cytology specimens revealed all mutations detected in tissue as well as additional mutations, and this suggested that urine might more effectively capture the full genetic heterogeneity of disease than an individual cystectomy. Alterations in multiple genes correlated with clinical and histopathological features, including responses to BCG treatment, flat architecture versus papillary architecture, and smoking history.
CONCLUSIONS: Urine specimens can replace tissue as a substrate for NGS analysis of HR NMIUC. Several genomic alterations identified in urine specimens might be associated with histological features and clinical characteristics. Cancer Cytopathol 2017. © 2017 American Cancer Society.

PMID: 28339163 [PubMed - as supplied by publisher]

Exome sequencing in Thai patients with familial obesity.

Genet Mol Res. 2016 Jul 14;15(2):

Authors: Kaewsutthi S, Santiprabhob J, Phonrat B, Tungtrongchitr A, Lertrit P, Tungtrongchitr R

Abstract
Obesity is a major worldwide health issue, with increasing prevalence in adults and children from developed and developing countries. Obesity causes several chronic diseases, including cardiovascular and respiratory diseases, osteoarthritis, hypertension, stroke, type II diabetes, obstructive sleep apnea, and several types of cancer. Previous genome-wide association studies have identified several genes associated with obesity, including LEP, LEPR, POMC, PCSK1, FTO, MC3R, MC4R, GNPDA2, TMEM18, QPCTL/GIPR, BDNF, ETV5, MAP2K5/SKOR1, SEC16B, SIM1, and TNKS/MSRA. However, most of these variants are found in the intronic or intergenic regions, making it difficult to elucidate the underlying mechanisms. Therefore, in this study, we performed a whole exome sequencing of the protein-coding regions in the total genome (exome) of two obese and one normal subject belonging to the same Thai family to identify the genes responsible for obesity. We identified 709 functional variants that were differentially expressed between obese and normal subjects; of these, 65 were predicted to be deleterious to protein structure or function. The minor allele frequency of 14 of these genes (ALOX5AP, COL9A2, DEFB126, GDPD4, HCRTR1, MLL3, OPLAH, OR4C45, PRIM2, RXFP2, TIGD6, TRPM8, USP49, and ZNF596) was low, indicating causal variants that could be associated with complex traits or diseases. Genotyping revealed HCRTR1, COL9A2, and TRPM8 to be associated with the regulation of feeding behavior and energy expenditure. These genes constituted a network of pathways, including lipid metabolism, signaling transduction, immune, membrane transport, and gene regulation pathways, and seemed to play important roles in obesity.

PMID: 27421018 [PubMed - indexed for MEDLINE]

TBR1 regulates autism risk genes in the developing neocortex.

Genome Res. 2016 08;26(8):1013-22

Authors: Notwell JH, Heavner WE, Darbandi SF, Katzman S, McKenna WL, Ortiz-Londono CF, Tastad D, Eckler MJ, Rubenstein JL, McConnell SK, Chen B, Bejerano G

Abstract
Exome sequencing studies have identified multiple genes harboring de novo loss-of-function (LoF) variants in individuals with autism spectrum disorders (ASD), including TBR1, a master regulator of cortical development. We performed ChIP-seq for TBR1 during mouse cortical neurogenesis and show that TBR1-bound regions are enriched adjacent to ASD genes. ASD genes were also enriched among genes that are differentially expressed in Tbr1 knockouts, which together with the ChIP-seq data, suggests direct transcriptional regulation. Of the nine ASD genes examined, seven were misexpressed in the cortices of Tbr1 knockout mice, including six with increased expression in the deep cortical layers. ASD genes with adjacent cortical TBR1 ChIP-seq peaks also showed unusually low levels of LoF mutations in a reference human population and among Icelanders. We then leveraged TBR1 binding to identify an appealing subset of candidate ASD genes. Our findings highlight a TBR1-regulated network of ASD genes in the developing neocortex that are relatively intolerant to LoF mutations, indicating that these genes may play critical roles in normal cortical development.

PMID: 27325115 [PubMed - indexed for MEDLINE]

ZNHIT3 is defective in PEHO syndrome, a severe encephalopathy with cerebellar granule neuron loss.

Brain. 2017 Mar 01;:

Authors: Anttonen AK, Laari A, Kousi M, Yang YJ, Jääskeläinen T, Somer M, Siintola E, Jakkula E, Muona M, Tegelberg S, Lönnqvist T, Pihko H, Valanne L, Paetau A, Lun MP, Hästbacka J, Kopra O, Joensuu T, Katsanis N, Lehtinen MK, Palvimo JJ, Lehesjoki AE

Abstract
Progressive encephalopathy with oedema, hypsarrhythmia, and optic atrophy (PEHO) syndrome is an early childhood onset, severe autosomal recessive encephalopathy characterized by extreme cerebellar atrophy due to almost total granule neuron loss. By combining homozygosity mapping in Finnish families with Sanger sequencing of positional candidate genes and with exome sequencing a homozygous missense substitution of leucine for serine at codon 31 in ZNHIT3 was identified as the primary cause of PEHO syndrome. ZNHIT3 encodes a nuclear zinc finger protein previously implicated in transcriptional regulation and in small nucleolar ribonucleoprotein particle assembly and thus possibly to pre-ribosomal RNA processing. The identified mutation affects a highly conserved amino acid residue in the zinc finger domain of ZNHIT3. Both knockdown and genome editing of znhit3 in zebrafish embryos recapitulate the patients' cerebellar defects, microcephaly and oedema. These phenotypes are rescued by wild-type, but not mutant human ZNHIT3 mRNA, suggesting that the patient missense substitution causes disease through a loss-of-function mechanism. Transfection of cell lines with ZNHIT3 expression vectors showed that the PEHO syndrome mutant protein is unstable. Immunohistochemical analysis of mouse cerebellar tissue demonstrated ZNHIT3 to be expressed in proliferating granule cell precursors, in proliferating and post-mitotic granule cells, and in Purkinje cells. Knockdown of Znhit3 in cultured mouse granule neurons and ex vivo cerebellar slices indicate that ZNHIT3 is indispensable for granule neuron survival and migration, consistent with the zebrafish findings and patient neuropathology. These results suggest that loss-of-function of a nuclear regulator protein underlies PEHO syndrome and imply that establishment of its spatiotemporal interaction targets will be the basis for developing therapeutic approaches and for improved understanding of cerebellar development.

PMID: 28335020 [PubMed - as supplied by publisher]

Mutations in the leukemia inhibitory factor receptor (LIFR) gene and Lifr deficiency cause urinary tract malformations.

Hum Mol Genet. 2017 Mar 08;:

Authors: Kosfeld A, Brand F, Weiss AC, Kreuzer M, Goerk M, Martens H, Schubert S, Schäfer AK, Riehmer V, Hennies I, Bräsen JH, Pape L, Amann K, Krogvold L, Bjerre A, Daniel C, Kispert A, Haffner D, Weber RG

Abstract
Congenital anomalies of the kidneys and urinary tract (CAKUT) are the most common cause of chronic kidney disease in children. As CAKUT is a genetically heterogeneous disorder and most cases are genetically unexplained, we aimed to identify new CAKUT causing genes. Using whole-exome sequencing and trio-based de novo analysis, we identified a novel heterozygous de novo frameshift variant in the leukemia inhibitory factor receptor (LIFR) gene causing instability of the mRNA in a patient presenting with bilateral CAKUT and requiring kidney transplantation at one year of age. LIFR encodes a transmembrane receptor utilized by IL-6 family cytokines, mainly by the leukemia inhibitory factor (LIF). Mutational analysis of 121 further patients with severe CAKUT yielded two rare heterozygous LIFR missense variants predicted to be pathogenic in three unrelated patients. LIFR mutants showed decreased half-life and cell membrane localization resulting in reduced LIF-stimulated STAT3 phosphorylation. LIFR showed high expression in human fetal kidney and the human ureter, and was also expressed in the developing murine urogenital system. Lifr knockout mice displayed urinary tract malformations including hydronephrosis, hydroureter, ureter ectopia, and, consistently, reduced ureteral lumen and muscular hypertrophy, similar to the phenotypes observed in patients carrying LIFR variants. Additionally, a form of cryptorchidism was detected in all Lifr-/- mice and the patient carrying the LIFR frameshift mutation. Altogether, we demonstrate heterozygous novel or rare LIFR mutations in 3.3% of CAKUT patients, and provide evidence that Lifr deficiency and deactivating LIFR mutations cause highly similar anomalies of the urogenital tract in mice and humans.

PMID: 28334964 [PubMed - as supplied by publisher]

Clinical and genetic characterization of leukoencephalopathies in adults.

Brain. 2017 Mar 02;:

Authors: Lynch DS, Rodrigues Brandão de Paiva A, Zhang WJ, Bugiardini E, Freua F, Tavares Lucato L, Macedo-Souza LI, Lakshmanan R, Kinsella JA, Merwick A, Rossor AM, Bajaj N, Herron B, McMonagle P, Morrison PJ, Hughes D, Pittman A, Laurà M, Reilly MM, Warren JD, Mummery CJ, Schott JM, Adams M, Fox NC, Murphy E, Davagnanam I, Kok F, Chataway J, Houlden H

Abstract
Leukodystrophies and genetic leukoencephalopathies are a rare group of disorders leading to progressive degeneration of cerebral white matter. They are associated with a spectrum of clinical phenotypes dominated by dementia, psychiatric changes, movement disorders and upper motor neuron signs. Mutations in at least 60 genes can lead to leukoencephalopathy with often overlapping clinical and radiological presentations. For these reasons, patients with genetic leukoencephalopathies often endure a long diagnostic odyssey before receiving a definitive diagnosis or may receive no diagnosis at all. In this study, we used focused and whole exome sequencing to evaluate a cohort of undiagnosed adult patients referred to a specialist leukoencephalopathy service. In total, 100 patients were evaluated using focused exome sequencing of 6100 genes. We detected pathogenic or likely pathogenic variants in 26 cases. The most frequently mutated genes were NOTCH3, EIF2B5, AARS2 and CSF1R. We then carried out whole exome sequencing on the remaining negative cases including four family trios, but could not identify any further potentially disease-causing mutations, confirming the equivalence of focused and whole exome sequencing in the diagnosis of genetic leukoencephalopathies. Here we provide an overview of the clinical and genetic features of these disorders in adults.

PMID: 28334938 [PubMed - as supplied by publisher]

SLC30A9 mutation affecting intracellular zinc homeostasis causes a novel cerebro-renal syndrome.

Brain. 2017 Feb 09;:

Authors: Perez Y, Shorer Z, Liani-Leibson K, Chabosseau P, Kadir R, Volodarsky M, Halperin D, Barber-Zucker S, Shalev H, Schreiber R, Gradstein L, Gurevich E, Zarivach R, Rutter GA, Landau D, Birk OS

Abstract
A novel autosomal recessive cerebro-renal syndrome was identified in consanguineous Bedouin kindred: neurological deterioration was evident as of early age, progressing into severe intellectual disability, profound ataxia, camptocormia and oculomotor apraxia. Brain MRI was normal. Four of the six affected individuals also had early-onset nephropathy with features of tubulo-interstitial nephritis, hypertension and tendency for hyperkalemia, though none had rapid deterioration of renal function. Genome wide linkage analysis identified an ∼18 Mb disease-associated locus on chromosome 4 (maximal logarithm of odds score 4.4 at D4S2971; θ = 0). Whole exome sequencing identified a single mutation in SLC30A9 within this locus, segregating as expected within the kindred and not found in a homozygous state in 300 Bedouin controls. We showed that SLC30A9 (solute carrier family 30 member 9; also known as ZnT-9) is ubiquitously expressed with high levels in cerebellum, skeletal muscle, thymus and kidney. Confocal analysis of SH-SY5Y cells overexpressing SLC30A9 fused to enhanced green fluorescent protein demonstrated vesicular cytosolic localization associated with the endoplasmic reticulum, not co-localizing with endosomal or Golgi markers. SLC30A9 encodes a putative zinc transporter (by similarity) previously associated with Wnt signalling. However, using dual-luciferase reporter assay in SH-SY5Y cells we showed that Wnt signalling was not affected by the mutation. Based on protein modelling, the identified mutation is expected to affect SLC30A9's highly conserved cation efflux domain, putatively disrupting its transmembrane helix structure. Cytosolic Zn2+ measurements in HEK293 cells overexpressing wild-type and mutant SLC30A9 showed lower zinc concentration within mutant rather than wild-type SLC30A9 cells. This suggests that SLC30A9 has zinc transport properties affecting intracellular zinc homeostasis, and that the molecular mechanism of the disease is through defective function of this novel activity of SLC30A9 rather than by a defect in its previously described role in transcriptional activation of Wnt signalling.

PMID: 28334855 [PubMed - as supplied by publisher]

Hereditary spastic paraplegia caused by compound heterozygous mutations outside the motor domain of the KIF1A gene.

Eur J Neurol. 2017 Mar 22;:

Authors: Krenn M, Zulehner G, Hotzy C, Rath J, Stogmann E, Wagner M, Haack TB, Strom TM, Zimprich A, Zimprich F

Abstract
BACKGROUND AND PURPOSE: Hereditary spastic paraplegia is a clinically and genetically heterogeneous group of rare, inherited disorders causing an upper motor neuron syndrome with (complex) or without (pure) additional neurological symptoms. Mutations in the KIF1A gene have already been associated with recessive and dominant forms of hereditary spastic paraplegia (SPG30) in a few cases.
METHODS: All family members included in the study were examined neurologically. Whole-exome sequencing was used in affected individuals to identify the responsible candidate gene. Conventional Sanger sequencing was conducted to validate familial segregation.
RESULTS: A family of Macedonian origin with two affected siblings, one with slowly progressive and the other one with a more complex and rapidly progressing hereditary spastic paraplegia is reported. In both affected individuals, two novel pathogenic mutations outside the motor domain of the KIF1A gene were found (NM_001244008.1:c.2909G>A, p.Arg970His and c.1214dup, p.Asn405Lysfs*40) that segregate with the disease within the family establishing the diagnosis of autosomal recessive SPG30.
CONCLUSIONS: This report provides the first evidence that mutations outside the motor domain of the gene can cause (recessive) SPG30 and extends the genotype-phenotype association for KIF1A-related diseases.

PMID: 28332297 [PubMed - as supplied by publisher]

Mutations in EFL1, an SBDS partner, are associated with infantile pancytopenia, exocrine pancreatic insufficiency and skeletal anomalies in a Shwachman-Diamond like syndrome.

J Med Genet. 2017 Mar 22;:

Authors: Stepensky P, Chacón-Flores M, Kim KH, Abuzaitoun O, Bautista-Santos A, Simanovsky N, Siliqi D, Altamura D, Méndez-Godoy A, Gijsbers A, Naser Eddin A, Dor T, Charrow J, Sánchez-Puig N, Elpeleg O

Abstract
BACKGROUND: For the final step of the maturation of the ribosome, the nascent 40S and 60S subunits are exported from the nucleus to the cell cytoplasm. To prevent premature association of these ribosomal subunits, eukaryotic initiation factor 6 (eIF6) binds the 60S subunit within the nucleus. Its release in the cytoplasm requires the interaction of EFL1 and SDBS proteins. In Shwachman-Diamond syndrome (SDS), a defective SDBS protein prevents eIF6 eviction, inhibiting its recycle to the nucleus and subsequent formation of the active 80S ribosome.
OBJECTIVE: This study aims to identify the molecular basis of an SDS-like disease, manifested by pancytopenia, exocrine pancreatic insufficiency and skeletal abnormalities in six patients from three unrelated families.
METHODS: Whole exome analysis was used for mutation identification. Fluorescence microscopy studies assessed the localisation of Tif6-GFP, the yeast eIF6 homologue, in yeast WT and mutant cells. Human and yeast EFL1 proteins, WT and mutants, were expressed in Saccharomyces cerevisiae BCY123 strain, and circular dichroism and small-angle X-ray scattering were used to assess the folding and flexibility of these proteins. Green malachite colorimetric assay was performed to determine the GTPase activity of WT and Efl1 mutants.
RESULTS: Four patients were homozygous for p.R1095Q variant and two patients were homozygous for p.M882K variant in EFL1. Residue R1095 and M882 are conserved across species. Neither the GTPase activity of the mutant proteins nor its activation by the SDBD protein or the 60S ribosomal subunit were affected. Complementation of efl1Δ yeast cells with the EFL1 mutants rescued the slow growth phenotype. Nonetheless, Tif6-GFP was relocalised to the cytoplasm in mutant yeast cells in contrast to its nuclear localisation in WT cells.
CONCLUSIONS: Mutations in EFL1 clinically manifest as SDS-like phenotype. Similar to the molecular pathology of SDS, mutant EFL1 proteins do not promote the release of cytoplasmic Tif6 from the 60S subunit, likely preventing the formation of mature ribosomes.

PMID: 28331068 [PubMed - as supplied by publisher]

Personalized In Vitro and In Vivo Cancer Models to Guide Precision Medicine.

Cancer Discov. 2017 Mar 22;:

Authors: Pauli C, Hopkins BD, Prandi D, Shaw R, Fedrizzi T, Sboner A, Sailer V, Augello M, Puca L, Rosati R, McNary TJ, Churakova Y, Cheung C, Triscott J, Pisapia D, Rao R, Mosquera JM, Robinson B, Faltas BM, Emerling BE, Gadi VK, Bernard B, Elemento O, Beltran H, Demichelis F, Kemp CJ, Grandori C, Cantley LC, Rubin MA

Abstract
Precision medicine is an approach that takes into account the influence of individuals' genes, environment, and lifestyle exposures to tailor interventions. Here, we describe the development of a robust precision cancer care platform that integrates whole-exome sequencing with a living biobank that enables high-throughput drug screens on patient-derived tumor organoids. To date, 56 tumor-derived organoid cultures and 19 patient-derived xenograft (PDX) models have been established from the 769 patients enrolled in an Institutional Review Board-approved clinical trial. Because genomics alone was insufficient to identify therapeutic options for the majority of patients with advanced disease, we used high-throughput drug screening to discover effective treatment strategies. Analysis of tumor-derived cells from four cases, two uterine malignancies and two colon cancers, identified effective drugs and drug combinations that were subsequently validated using 3-D cultures and PDX models. This platform thereby promotes the discovery of novel therapeutic approaches that can be assessed in clinical trials and provides personalized therapeutic options for individual patients where standard clinical options have been exhausted.SIGNIFICANCE: Integration of genomic data with drug screening from personalized in vitro and in vivo cancer models guides precision cancer care and fuels next-generation research. Cancer Discov; 7(5); 1-16. ©2017 AACR.

PMID: 28331002 [PubMed - as supplied by publisher]

Outcomes of Diagnostic Exome Sequencing in Patients With Diagnosed or Suspected Autism Spectrum Disorders.

Pediatr Neurol. 2017 Feb 08;:

Authors: Rossi M, El-Khechen D, Black MH, Farwell Hagman KD, Tang S, Powis Z

Abstract
BACKGROUND: Exome sequencing has recently been proved to be a successful diagnostic method for complex neurodevelopmental disorders. However, the diagnostic yield of exome sequencing for autism spectrum disorders has not been extensively evaluated in large cohorts to date.
MATERIALS AND METHODS: We performed diagnostic exome sequencing in a cohort of 163 individuals with autism spectrum disorder (66.3%) or autistic features (33.7%).
RESULTS: The diagnostic yield observed in patients in our cohort was 25.8% (42 of 163) for positive or likely positive findings in characterized disease genes, while a candidate genetic etiology was reported for an additional 3.3% (4 of 120) of patients. Among the positive findings in the patients with autism spectrum disorder or autistic features, 61.9% were the result of de novo mutations. Patients presenting with psychiatric conditions or ataxia or paraplegia in addition to autism spectrum disorder or autistic features were significantly more likely to receive positive results compared with patients without these clinical features (95.6% vs 27.1%, P < 0.0001; 83.3% vs 21.2%, P < 0.0001, respectively). The majority of the positive findings were in recently identified autism spectrum disorder genes, supporting the importance of diagnostic exome sequencing for patients with autism spectrum disorder or autistic features as the causative genes might evade traditional sequential or panel testing.
CONCLUSIONS: These results suggest that diagnostic exome sequencing would be an efficient primary diagnostic method for patients with autism spectrum disorders or autistic features. Moreover, our data may aid clinicians to better determine which subset of patients with autism spectrum disorder with additional clinical features would benefit the most from diagnostic exome sequencing.

PMID: 28330790 [PubMed - as supplied by publisher]