GUCA1A mutation causes maculopathy in a five-generation family with a wide spectrum of severity.

Genet Med. 2017 Aug;19(8):945-954

Authors: Chen X, Sheng X, Zhuang W, Sun X, Liu G, Shi X, Huang G, Mei Y, Li Y, Pan X, Liu Y, Li Z, Zhao Q, Yan B, Zhao C

Abstract
PURPOSE: The aim of this study was to investigate the genetic basis and pathogenic mechanism of variable maculopathies, ranging from mild photoreceptor degeneration to central areolar choroidal dystrophy, in a five-generation family.
METHODS: Clinical characterizations, whole-exome sequencing, and genome-wide linkage analysis were carried out on the family. Zebrafish models were used to investigate the pathogenesis of GUCA1A mutations.
RESULTS: A novel mutation, GUCA1A p.R120L, was identified in the family and predicted to alter the tertiary structure of guanylyl cyclase-activating protein 1, a photoreceptor-expressed protein encoded by the GUCA1A gene. The mutation was shown in zebrafish to cause significant disruptions in photoreceptors and retinal pigment epithelium, together with atrophies of retinal vessels and choriocapillaris. Those phenotypes could not be fully rescued by exogenous wild-type GUCA1A, suggesting a likely gain-of-function mechanism for p.R120L. GUCA1A p.D100E, another mutation previously implicated in cone dystrophy, also impaired the retinal pigment epithelium and photoreceptors in zebrafish, but probably via a dominant negative effect.
CONCLUSION: We conclude that GUCA1A mutations could cause significant variability in maculopathies, including central areolar choroidal dystrophy, which represents a severe pattern of maculopathy. The diverse pathogenic modes of GUCA1A mutations may explain the phenotypic diversities.Genet Med advance online publication 26 January 2017.

PMID: 28125083 [PubMed - indexed for MEDLINE]

Genetic invalidation of Lp-PLA2 as a therapeutic target: Large-scale study of five functional Lp-PLA2-lowering alleles.

Eur J Prev Cardiol. 2017 Mar;24(5):492-504

Authors: Gregson JM, Freitag DF, Surendran P, Stitziel NO, Chowdhury R, Burgess S, Kaptoge S, Gao P, Staley JR, Willeit P, Nielsen SF, Caslake M, Trompet S, Polfus LM, Kuulasmaa K, Kontto J, Perola M, Blankenberg S, Veronesi G, Gianfagna F, Männistö S, Kimura A, Lin H, Reilly DF, Gorski M, Mijatovic V, CKDGen consortium, Munroe PB, Ehret GB, International Consortium for Blood Pressure, Thompson A, Uria-Nickelsen M, Malarstig A, Dehghan A, CHARGE inflammation working group, Vogt TF, Sasaoka T, Takeuchi F, Kato N, Yamada Y, Kee F, Müller-Nurasyid M, Ferrières J, Arveiler D, Amouyel P, Salomaa V, Boerwinkle E, Thompson SG, Ford I, Wouter Jukema J, Sattar N, Packard CJ, Shafi Majumder AA, Alam DS, Deloukas P, Schunkert H, Samani NJ, Kathiresan S, MICAD Exome consortium, Nordestgaard BG, Saleheen D, Howson JM, Di Angelantonio E, Butterworth AS, Danesh J, EPIC-CVD consortium and the CHD Exome+ consortium

Abstract
Aims Darapladib, a potent inhibitor of lipoprotein-associated phospholipase A2 (Lp-PLA2), has not reduced risk of cardiovascular disease outcomes in recent randomized trials. We aimed to test whether Lp-PLA2 enzyme activity is causally relevant to coronary heart disease. Methods In 72,657 patients with coronary heart disease and 110,218 controls in 23 epidemiological studies, we genotyped five functional variants: four rare loss-of-function mutations (c.109+2T > C (rs142974898), Arg82His (rs144983904), Val279Phe (rs76863441), Gln287Ter (rs140020965)) and one common modest-impact variant (Val379Ala (rs1051931)) in PLA2G7, the gene encoding Lp-PLA2. We supplemented de-novo genotyping with information on a further 45,823 coronary heart disease patients and 88,680 controls in publicly available databases and other previous studies. We conducted a systematic review of randomized trials to compare effects of darapladib treatment on soluble Lp-PLA2 activity, conventional cardiovascular risk factors, and coronary heart disease risk with corresponding effects of Lp-PLA2-lowering alleles. Results Lp-PLA2 activity was decreased by 64% ( p = 2.4 × 10-25) with carriage of any of the four loss-of-function variants, by 45% ( p < 10-300) for every allele inherited at Val279Phe, and by 2.7% ( p = 1.9 × 10-12) for every allele inherited at Val379Ala. Darapladib 160 mg once-daily reduced Lp-PLA2 activity by 65% ( p < 10-300). Causal risk ratios for coronary heart disease per 65% lower Lp-PLA2 activity were: 0.95 (0.88-1.03) with Val279Phe; 0.92 (0.74-1.16) with carriage of any loss-of-function variant; 1.01 (0.68-1.51) with Val379Ala; and 0.95 (0.89-1.02) with darapladib treatment. Conclusions In a large-scale human genetic study, none of a series of Lp-PLA2-lowering alleles was related to coronary heart disease risk, suggesting that Lp-PLA2 is unlikely to be a causal risk factor.

PMID: 27940953 [PubMed - indexed for MEDLINE]

Congenital Sucrase-isomaltase Deficiency: A Novel Compound Heterozygous Mutation Causing Aberrant Protein Localization.

J Pediatr Gastroenterol Nutr. 2017 May;64(5):770-776

Authors: Haberman Y, Di Segni A, Loberman-Nachum N, Barel O, Kunik V, Eyal E, Kol N, Hout-Siloni G, Kochavi B, Avivi C, Schvimer M, Rechavi G, Anikster Y, Barshack I, Weiss B

Abstract
OBJECTIVES: Congenital diarrheal disorders is a group of inherited enteropathies presenting in early life and requiring parenteral nutrition. In most cases, genetics may be the key for precise diagnosis. We present an infant girl with chronic congenital diarrhea that resolved after introduction of fructose-based formula but had no identified mutation in the SLC5A1 gene. Using whole exome sequencing (WES) we identified other mutations that better dictated dietary adjustments.
METHODS: WES of the patient and her parents was performed. The analysis focused on recessive model including compound heterozygous mutations. Sanger sequencing was used to validate identified mutations and to screen the patient's newborn sister and grandparents. Expression and localization analysis were performed in the patient's duodenal biopsies using immunohistochemistry.
RESULTS: Using WES we identified a new compound heterozygote mutation in sucrase-isomaltase (SI) gene; a maternal inherited known V577G mutation, and a novel paternal inherited C1531W mutation. Importantly, the newborn offspring carried similar compound heterozygous mutations. Computational predictions suggest that both mutations highly destabilize the protein. SI expression and localization studies determined that the mutated SI protein was not expressed on the brush border membrane in the patient's duodenal biopsies, verifying the diagnosis of congenital sucrase-isomaltase deficiency (CSID).
CONCLUSIONS: The novel compound heterozygote V577G/C1531W SI mutations lead to lack of SI expression in the duodenal brush border, confirming the diagnosis of CSID. These cases of CSID extend the molecular spectrum of this condition, further directing a more adequate dietary intervention for the patient and newborn sibling.

PMID: 27749612 [PubMed - indexed for MEDLINE]

Nonlinear tumor evolution from dysplastic nodules to hepatocellular carcinoma.

Oncotarget. 2017 Jan 10;8(2):2076-2082

Authors: Joung JG, Ha SY, Bae JS, Nam JY, Gwak GY, Lee HO, Son DS, Park CK, Park WY

Abstract
Dysplastic nodules are premalignant neoplastic nodules found in explanted livers with cirrhosis. Genetic signatures of premalignant dysplastic nodules (DNs) with concurrent hepatocellular carcinoma (HCC) may provide an insight in the molecular evolution of hepatocellular carcinogenesis. We analyzed four patients with multifocal nodular lesions and cirrhotic background by whole-exome sequencing (WES). The genomic profiles of somatic single nucleotide variations (SNV) and copy number variations (CNV) in DNs were compared to those of HCCs. The number and variant allele frequency of somatic SNVs of DNs and HCCs in each patient was identical along the progression of pathological grade. The somatic SNVs in DNs showed little conservation in HCC. Additionally, CNVs showed no conservation. Phylogenetic analysis based on SNVs and copy number profiles indicated a nonlinear segregation pattern, implying independent development of DNs and HCC in each patient. Thus, somatic mutations in DNs may be developed separately from other malignant nodules in the same liver, suggesting a nonlinear model for hepatocarcinogenesis from DNs to HCC.

PMID: 27409339 [PubMed - indexed for MEDLINE]

First-Line Cetuximab Monotherapy in KRAS/NRAS/BRAF Mutation-Negative Colorectal Cancer Patients.

Clin Drug Investig. 2018 Feb 22;:

Authors: Moiseyenko VM, Moiseyenko FV, Yanus GA, Kuligina ES, Sokolenko AP, Bizin IV, Kudriavtsev AA, Aleksakhina SN, Volkov NM, Chubenko VA, Kozyreva KS, Kramchaninov MM, Zhuravlev AS, Shelekhova KV, Pashkov DV, Ivantsov AO, Venina AR, Sokolova TN, Preobrazhenskaya EV, Mitiushkina NV, Togo AV, Iyevleva AG, Imyanitov EN

Abstract
BACKGROUND: Colorectal carcinomas (CRCs) are sensitive to treatment by anti-epidermal growth factor receptor (EGFR) antibodies only if they do not carry activating mutations in down-stream EGFR targets (KRAS/NRAS/BRAF). Most clinical trials for chemo-naive CRC patients involved combination of targeted agents and chemotherapy, while single-agent cetuximab or panitumumab studies included either heavily pretreated patients or subjects who were not selected on the basis of molecular tests. We hypothesized that anti-EGFR therapy would have significant efficacy in chemo-naive patients with KRAS/NRAS/BRAF mutation-negative CRC.
METHODS: Nineteen patients were prospectively included in the study.
RESULTS: Two (11%) patients experienced partial response (PR) and 11 (58%) subjects showed stable disease (SD). Median time to progression approached 6.1 months (range 1.6-15.0 months). Cetuximab efficacy did not correlate with RNA expression of EGFR and insulin-like growth factor 2 (IGF2). Only one tumor carried PIK3CA mutation, and this CRC responded to cetuximab. Exome analysis of patients with progressive disease (PD) revealed 1 CRC with high-level microsatellite instability and 1 instance of HER2 oncogene amplification; 3 of 4 remaining patients with PD had allergic reactions to cetuximab, while none of the subjects with PR or SD had this complication. Comparison with 19 retrospective KRAS/NRAS/BRAF mutation-negative patients receiving first-line fluoropyrimidines revealed no advantages or disadvantages of cetuximab therapy.
CONCLUSIONS: Cetuximab demonstrates only modest efficacy when given as a first-line monotherapy to KRAS/NRAS/BRAF mutation-negative CRC patients. It is of question, why meticulous patient selection, which was undertaken in the current study, did not result in the improvement of outcomes of single-agent cetuximab treatment.

PMID: 29470838 [PubMed - as supplied by publisher]

Autosomal recessive Noonan syndrome associated with biallelic LZTR1 variants.

Genet Med. 2018 Feb 22;:

Authors: Johnston JJ, van der Smagt JJ, Rosenfeld JA, Pagnamenta AT, Alswaid A, Baker EH, Blair E, Borck G, Brinkmann J, Craigen W, Dung VC, Emrick L, Everman DB, van Gassen KL, Gulsuner S, Harr MH, Jain M, Kuechler A, Leppig KA, McDonald-McGinn DM, Can NTB, Peleg A, Roeder ER, Rogers RC, Sagi-Dain L, Sapp JC, Schäffer AA, Schanze D, Stewart H, Taylor JC, Verbeek NE, Walkiewicz MA, Zackai EH, Zweier C, Members of the Undiagnosed Diseases Network, Zenker M, Lee B, Biesecker LG

Abstract
PurposeTo characterize the molecular genetics of autosomal recessive Noonan syndrome.MethodsFamilies underwent phenotyping for features of Noonan syndrome in children and their parents. Two multiplex families underwent linkage analysis. Exome, genome, or multigene panel sequencing was used to identify variants. The molecular consequences of observed splice variants were evaluated by reverse-transcription polymerase chain reaction.ResultsTwelve families with a total of 23 affected children with features of Noonan syndrome were evaluated. The phenotypic range included mildly affected patients, but it was lethal in some, with cardiac disease and leukemia. All of the parents were unaffected. Linkage analysis using a recessive model supported a candidate region in chromosome 22q11, which includes LZTR1, previously shown to harbor mutations in patients with Noonan syndrome inherited in a dominant pattern. Sequencing analyses of 21 live-born patients and a stillbirth identified biallelic pathogenic variants in LZTR1, including putative loss-of-function, missense, and canonical and noncanonical splicing variants in the affected children, with heterozygous, clinically unaffected parents and heterozygous or normal genotypes in unaffected siblings.ConclusionThese clinical and genetic data confirm the existence of a form of Noonan syndrome that is inherited in an autosomal recessive pattern and identify biallelic mutations in LZTR1.Genet Med advance online publication, 22 February 2018; doi:10.1038/gim.2017.249.

PMID: 29469822 [PubMed - as supplied by publisher]

Characterization of a novel breast cancer cell line derived from a metastatic bone lesion of a breast cancer patient.

Breast Cancer Res Treat. 2018 Feb 21;:

Authors: Johnson J, Bessette DC, Saunus JM, Smart CE, Song S, Johnston RL, Cocciardi S, Rozali EN, Johnstone CN, Vargas AC, Kazakoff SH, BioBank VC, Khanna KK, Lakhani SR, Chenevix-Trench G, Simpson PT, Nones K, Waddell N, Al-Ejeh F

Abstract
PURPOSE: We aimed to generate and characterize a novel cell line from a breast cancer bone metastasis to better study the progression of the disease.
METHODS: The cell line, P7731, was derived from a metastatic bone lesion of a breast cancer patient and assessed for marker expression. P7731 was analyzed for DNA copy number variation, somatic mutations, and gene expression and was compared with the primary tumor.
RESULTS: P7731 cells are negative for estrogen receptor alpha (ERα), progesterone receptor (PR), and HER2 (triple-negative); strongly express vimentin (100% of cells positive) and also express cytokeratins 8/18 and 19 but at lower frequencies. Flow cytometry indicates P7731 cells are predominantly CD44+/CD49f+/EpCAM-, consistent with a primitive, mesenchymal-like phenotype. The cell line is tumorigenic in immunocompromised mice. Exome sequencing identified a total of 45 and 76 somatic mutations in the primary tumor and cell line, respectively, of which 32 were identified in both samples and included mutations in known driver genes PIK3CA, TP53, and ARID1A. P7731 retains the DNA copy number alterations present in the matching primary tumor. Homozygous deletions detected in the cell line and in the primary tumor were found in regions containing three known (CDKN2A, CDKN2B, and CDKN1B) and 23 putative tumor suppressor genes. Cell line-specific gene amplification coupled with mRNA expression analysis revealed genes and pathways with potential pro-metastatic functions.
CONCLUSION: This novel human breast cancer-bone metastasis cell line will be a useful model to study aspects of breast cancer biology, particularly metastasis-related changes from breast to bone.

PMID: 29468485 [PubMed - as supplied by publisher]

Atherosclerosis Is an Inflammatory Disease which Lacks a Common Anti-inflammatory Therapy: How Human Genetics Can Help to This Issue. A Narrative Review.

Front Pharmacol. 2018;9:55

Authors: Fava C, Montagnana M

Abstract
Atherosclerosis is a multifactorial disease triggered and sustained by different risk factors such as dyslipidemia, arterial hypertension, diabetes mellitus, smoke, etc. Since a couple of decades, a pivotal role for inflammation in its pathogenesis has been recognized and proved at molecular levels, and already described in many animal models. Despite all this knowledge, due to the complexity of the specific inflammatory process subtending atherosclerosis and to the fact that inflammation is also a protective response against microorganisms, no anti-inflammatory therapy has been rendered available in the therapeutic armamentarium against atherosclerosis and vascular events till 2017 when canakinumab in the first ad-hoc randomized clinical trial (RCT) proved for the first time that targeting specifically inflammation lowers cardiovascular (CV) events. From the genetic side, in the 90's and early 2000, several genetic markers in inflammatory pathway have been explored searching for an association with athero-thrombosis which gave seldom consistent results. Then, in the genomic era, plenty of genetic markers covering most of the genome have been analyzed at once without a priori information. The results coming from genome wide association studies (GWAS) have pinpointed some loci closed to inflammatory molecules consistently associated with atherosclerosis and CV consequences revamping the strict link between inflammation and atherosclerosis and suggesting some tailored target therapy. Whole-exome and whole-genome sequencing will come soon showing new and old loci associated with atherosclerosis suggesting new molecular targets or underlying which inflammatory pathway could be most attractive to target for blocking atherosclerosis even in its early stages.

PMID: 29467655 [PubMed]

Whole exome sequencing reveals novel somatic alterations in neuroblastoma patients with chemotherapy.

Cancer Cell Int. 2018;18:21

Authors: Duan C, Wang H, Chen Y, Chu P, Xing T, Gao C, Yue Z, Zheng J, Jin M, Gu W, Ma X

Abstract
Background: We ought to explore the acquired somatic alterations, shedding light on genetic basis of somatic alterations in NB patients with chemotherapy.
Methods: Marrow blood samples from NB patients were collected before treatment, after the 2nd and 4th chemotherapy for baseline research and continuous monitoring by whole exome sequencing. Plasma cell free DNA (cfDNA) was prepared for baseline research. Finger nail cells were extracted as self control. The clinical data was analyzed.
Results: From December 2014 to February 2016, 27 cases of children with stage IV NB were diagnosed. The follow up time ranged from 5 to 25 months, with a median follow up time of 17 months, 20 patients were stable, one patient died of pulmonary embolism during surgery, six patients died of disease progression. Marrow blood whole exome sequencing demonstrated that several novel somatic mutations were identified in all three trios comply or against the trendy of tumor size variation. Of note, six recurrent mutations in bromodomain PHD finger transcription factor (BPTF) were identified in nine NB patients under the continuous monitoring. The mutation rates variation was positively correlated to tumor size (CC = 0.428, P = 0.021), and patients with BPTF mutation may have a worse prognosis compared with wild type. Meanwhile, CGREF1, CUX2, GP1BA, SLC45A1 and TRA2A were mutated with the trendy oppose as therapeutic effects. The baseline research in three NB patients demonstrated that mutation rate of BPTF, TMCO3, GPRIN2 and C20orf96 in plasma cfDNA were in positive correlation with bone marrow genomic DNA (P = 0.001).
Conclusions: Our study showed that BPTF along with other mutations may function as a biomarker for evaluating to effects of chemotherapy to this refractory tumor, and patients with BPTF mutation might have a worse prognosis.

PMID: 29467591 [PubMed]

The exomic landscape of t(14;18)-negative diffuse follicular lymphoma with 1p36 deletion.

Br J Haematol. 2018 02;180(3):391-394

Authors: Zamò A, Pischimarov J, Horn H, Ott G, Rosenwald A, Leich E

Abstract
Predominantly diffuse t(14;18) negative follicular lymphoma (FL) with 1p36 deletion shows distinctive clinical, morphological and molecular features that distinguish it from classical FL. In order to investigate whether it possesses a unique mutation profile, we performed whole exome sequencing of six well-characterised cases. Our analysis showed that the mutational landscape of this subtype is largely distinct from classical FL. It appears to harbour several recurrent mutations, affecting STAT6, CREBBP and basal membrane protein genes with high frequency. Our data support the view that this FL subtype should be considered a separate entity from classical FL.

PMID: 29193015 [PubMed - indexed for MEDLINE]

Whole-exome sequencing identified mutational profiles of high-grade colon adenomas.

Oncotarget. 2017 Jan 24;8(4):6579-6588

Authors: Lee SH, Jung SH, Kim TM, Rhee JK, Park HC, Kim MS, Kim SS, An CH, Lee SH, Chung YJ

Abstract
Although gene-to-gene analyses identified genetic alterations such as APC, KRAS and TP53 mutations in colon adenomas, it is largely unknown whether there are any others in them. Mutational profiling of high-grade colon adenoma (HGCA) that just precedes colon carcinoma might identify not only novel adenoma-specific genes but also critical genes for its progression to carcinoma. For this, we performed whole-exome sequencing (WES) of 12 HGCAs and identified 11 non-hypermutated and one hypermutated (POLE-mutated) cases. We identified 22 genes including APC, KRAS, TP53, GNAS, NRAS, SMAD4, ARID2, and PIK3CA with non-silent mutations in the cancer Census Genes. Bi-allelic and mono-allelic APC alterations were found in nine and one HGCAs, respectively, while the other two harbored wild-type APC. Five HGCAs harbored either mono-allelic (four HGCAs) or bi-allelic (one HGCA) SMAD4 mutation or 18q loss that had been known as early carcinoma-specific changes. We identified MTOR, ACVR1B, GNAQ, ATM, CNOT1, EP300, ARID2, RET and MAP2K4 mutations for the first time in colon adenomas. Our WES data is largely matched with the earlier 'adenoma-carcinoma model' (APC, KRAS, NRAS and GNAS mutations), but there are newly identified SMAD4, MTOR, ACVR1B, GNAQ, ATM, CNOT1, EP300, ARID2, RET and MAP2K4 mutations in this study. Our findings provide resource for understanding colon premalignant lesions and for identifying genomic clues for differential diagnosis and therapy options for colon adenomas and carcinomas.

PMID: 28179590 [PubMed - indexed for MEDLINE]

Recurrent genetic defects on chromosome 5q in myeloid neoplasms.

Oncotarget. 2017 Jan 24;8(4):6483-6495

Authors: Hosono N, Makishima H, Mahfouz R, Przychodzen B, Yoshida K, Jerez A, LaFramboise T, Polprasert C, Clemente MJ, Shiraishi Y, Chiba K, Tanaka H, Miyano S, Sanada M, Cui E, Verma AK, McDevitt MA, List AF, Saunthararajah Y, Sekeres MA, Boultwood J, Ogawa S, Maciejewski JP

Abstract
BACKGROUND: Deletion of chromosome 5q (del(5q)) is the most common karyotypic abnormality in myeloid neoplasms.
MATERIALS AND METHODS: To define the pathogenic molecular features associated with del(5q), next-generation sequencing was applied to 133 patients with myeloid neoplasms (MDS; N = 69, MDS/MPN; N = 5, sAML; N = 29, pAML; N = 30) with del(5q) as a sole abnormally or a part of complex karyotype and results were compared to molecular features of patients diploid for chr5.
FINDINGS: A number of 5q genes with haploinsufficient expression and/or recurrent somatic mutations were identified; for these genes, CSNK1A1 and G3BP1 within the commonly deleted 5q region and DDX41 within a commonly retained region were most commonly affected by somatic mutations. These genes showed consistent haploinsufficiency in deleted cases; low expression/mutations of G3BP1 or DDX41 were associated with poor survival, likely due to decreased cellular function. The most common mutations on other chromosomes in patients with del(5q) included TP53, and mutations of FLT3 (ITD or TKD), NPM1 or TET2 and were mutually exclusive. Serial sequencing allowed for definition of clonal architecture and dynamics, in patients with exome sequencing allelic imbalance for informative SNPs facilitated simultaneous approximation of clonal size of del(5q) and clonal burden for somatic mutations.
INTERPRETATION: Our results illuminate the spectrum of molecular defects characteristic of del(5q), their clinical impact and succession of stepwise evolution.

PMID: 28031539 [PubMed - indexed for MEDLINE]

Intratumoral heterogeneity and chemoresistance in nonseminomatous germ cell tumor of the testis.

Oncotarget. 2016 Dec 27;7(52):86280-86289

Authors: Bilen MA, Hess KR, Campbell MT, Wang J, Broaddus RR, Karam JA, Ward JF, Wood CG, Choi SL, Rao P, Zhang M, Naing A, General R, Cauley DH, Lin SH, Logothetis CJ, Pisters LL, Tu SM

Abstract
BACKGROUND: Nonseminomatous germ cell tumor of the testis (NSGCT) is largely curable. However, a small group of patients develop refractory disease. We investigated the hypothesis that intratumoral heterogeneity contributes to the emergence of chemoresistance and the development of refractory tumor subtypes.
RESULTS: Our institution's records for January 2000 through December 2010 included 275 patients whose primary tumor showed pure embryonal carcinoma (pure E); mixed embryonal carcinoma, yolk sac tumor, and teratoma (EYT); or mixed embryonal carcinoma, yolk sac tumor, seminoma, and teratoma (EYST). Patients with EYST had the highest cancer-specific mortality rate (P = .001). They tended to undergo somatic transformation (P = .0007). Two of 5 patients with clinical stage I EYST who had developed recurrence during active surveillance died of their disease.
MATERIALS AND METHODS: In this retrospective study, we evaluated consecutive patients who had been diagnosed with the three most common histological phenotypes of NSGCT. Chemoresistance was defined as the presence of teratoma, viable germ cell tumor, or somatic transformation in the residual tumor or the development of progressive or relapsed disease after chemotherapy. In a separate prospective study, we performed next-generation sequencing on tumor samples from 39 patients to identify any actionable genetic mutations.
CONCLUSIONS: Our data suggest that patients with EYST in their primary tumor may harbor a potentially refractory NSGCT phenotype and are at increased risk of dying from disease. Despite intratumoral heterogeneity, improved patient selection and personalized care of distinct tumor subtypes may optimize the clinical outcome of patients with NSGCT.

PMID: 27861143 [PubMed - indexed for MEDLINE]

SCN3A deficiency associated with increased seizure susceptibility.

Neurobiol Dis. 2017 Jun;102:38-48

Authors: Lamar T, Vanoye CG, Calhoun J, Wong JC, Dutton SBB, Jorge BS, Velinov M, Escayg A, Kearney JA

Abstract
Mutations in voltage-gated sodium channels expressed highly in the brain (SCN1A, SCN2A, SCN3A, and SCN8A) are responsible for an increasing number of epilepsy syndromes. In particular, mutations in the SCN3A gene, encoding the pore-forming Nav1.3 α subunit, have been identified in patients with focal epilepsy. Biophysical characterization of epilepsy-associated SCN3A variants suggests that both gain- and loss-of-function SCN3A mutations may lead to increased seizure susceptibility. In this report, we identified a novel SCN3A variant (L247P) by whole exome sequencing of a child with focal epilepsy, developmental delay, and autonomic nervous system dysfunction. Voltage clamp analysis showed no detectable sodium current in a heterologous expression system expressing the SCN3A-L247P variant. Furthermore, cell surface biotinylation demonstrated a reduction in the amount of SCN3A-L247P at the cell surface, suggesting the SCN3A-L247P variant is a trafficking-deficient mutant. To further explore the possible clinical consequences of reduced SCN3A activity, we investigated the effect of a hypomorphic Scn3a allele (Scn3aHyp) on seizure susceptibility and behavior using a gene trap mouse line. Heterozygous Scn3a mutant mice (Scn3a+/Hyp) did not exhibit spontaneous seizures nor were they susceptible to hyperthermia-induced seizures. However, they displayed increased susceptibility to electroconvulsive (6Hz) and chemiconvulsive (flurothyl and kainic acid) induced seizures. Scn3a+/Hyp mice also exhibited deficits in locomotor activity and motor learning. Taken together, these results provide evidence that loss-of-function of SCN3A caused by reduced protein expression or deficient trafficking to the plasma membrane may contribute to increased seizure susceptibility.

PMID: 28235671 [PubMed - indexed for MEDLINE]

CYP3A4 mutation causes vitamin D-dependent rickets type 3.

J Clin Invest. 2018 Feb 20;:

Authors: Roizen JD, Li D, O'Lear L, Javaid MK, Shaw NJ, Ebeling PR, Nguyen HH, Rodda CP, Thummel KE, Thacher TD, Hakonarson H, Levine MA

Abstract
Genetic forms of vitamin D-dependent rickets (VDDRs) are due to mutations impairing activation of vitamin D or decreasing vitamin D receptor responsiveness. Here we describe two unrelated patients with early-onset rickets, reduced serum levels of the vitamin D metabolites 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, and deficient responsiveness to parent and activated forms of vitamin D. Neither patient had a mutation in any genes known to cause VDDR, however, using whole exome sequence analysis we identified a recurrent de novo missense mutation c.902T>C (p.I301T) in CYP3A4 in both subjects that alters the conformation of substrate-recognition-site 4 (SRS-4). In vitro, the mutant CYP3A4 oxidized 1,25-dihydroxyvitamin D with 10-fold greater activity than wild-type CYP3A4 and 2-fold greater activity than CYP24A1, the principal inactivator of vitamin D metabolites. As CYP3A4 mutations have not previously been linked to rickets, these findings provide new insight into vitamin D metabolism, and demonstrate that accelerated inactivation of vitamin D metabolites represents a previously undescribed mechanism for vitamin D deficiency.

PMID: 29461981 [PubMed - as supplied by publisher]

Genetic Analyses Identified a SALL4 Gene Mutation Associated with Holt-Oram Syndrome.

DNA Cell Biol. 2018 Feb 20;:

Authors: Li B, Chen S, Sun K, Xu R, Wu Y

Abstract
Holt-Oram syndrome (HOS) is an autosomal dominant disorder, which is characterized by deformities of upper limbs and congenital heart defects. Alterations of TBX5 gene have been identified to be the leading cause of HOS, while some cases could not be explained by TBX5 mutations. In our study, we preliminarily diagnosed a newborn baby, who had Tetralogy of Fallot, thumb agenesis, facial dysplasia, and right ear canal malformation, as HOS. Chromosome microarray analyses showed no pathological deletions or replications of chromosome segments; whole exome sequencing screened out six candidate genes that were involved in cardiac diseases or syndromes among which SALL4 has been reported as HOS related gene. We evaluated the pathogenicity of SALL4 mutant sites by series of software. The results indicated that SALL4-M143V may be a polymorphism site, and SALL4-R418C could cause disease. HOPE and SWISS PDB viewer showed that SALL4-R418C leads to changes in amino acid properties, loss of protein hydrogen bond, and functional impact of SALL4 zinc finger domain. These results further confirmed the pathogenic significance of SALL4-R418C mutant. When genetic analyses coupled with bioinformatic analyses, we identified a SALL4 gene rare mutation which might contribute to a newborn with HOS. Although some doubts need to be further discussed and explored, our study deepened the understanding of phenotype difference among syndromes and role of SALL4 mutations in disease occurrence.

PMID: 29461882 [PubMed - as supplied by publisher]

Text-mined phenotype annotation and vector-based similarity to improve identification of similar phenotypes and causative genes in monogenic disease patients.

Hum Mutat. 2018 Feb 20;:

Authors: Saklatvala JR, Dand N, Simpson MA

Abstract
The genetic diagnosis of rare monogenic diseases using exome/genome sequencing requires the true causal variant(s) to be identified from tens of thousands of observed variants. Typically a virtual gene panel approach is taken whereby only variants in genes known to cause phenotypes resembling the patient under investigation are considered. With the number of known monogenic gene-disease pairs exceeding 5000, manual curation of personalised virtual panels using exhaustive knowledge of the genetic basis of the human monogenic phenotypic spectrum is challenging. We present improved probabilistic methods for estimating phenotypic similarity based on Human Phenotype Ontology annotation. A limitation of existing methods for evaluating a disease's similarity to a reference set is that reference diseases are typically represented as a series of binary (present/absent) observations of phenotypic terms. We evaluate a quantified disease reference set, using term frequency in phenotypic text descriptions to approximate term relevance. We demonstrate an improved ability to identify related diseases through the use of a quantified reference set, and that vector space similarity measures perform better than established information content-based measures. These improvements enable the generation of bespoke virtual gene panels, facilitating more accurate and efficient interpretation of genomic variant profiles from individuals with rare Mendelian disorders. These methods are available online at https://atlas.genetics.kcl.ac.uk/~jake/cgi-bin/patient_sim.py This article is protected by copyright. All rights reserved.

PMID: 29460986 [PubMed - as supplied by publisher]

Truncating variants of the DLG4 gene are responsible for intellectual disability with marfanoid features.

Clin Genet. 2018 Feb 20;:

Authors: Sébastien M, Ange-Line B, Mirna A, Martin C, Elisabeth S, Cyril G, Anne-Marie G, Aude C, Perrine C, Delphine H, Anne F, Nada H, Antonio V, Frédéric TM, Christophe P, Yannis D, Christel TR, Laurence F

Abstract
Marfanoid habitus (MH) combined with intellectual disability (ID) is a genetically and clinically heterogeneous group of overlapping disorders. We performed exome sequencing in 33 trios and 31 single probands to identify novel genes specific to MH-ID. After the search for variants in OMIM genes and non-OMIM genes with classical approaches, we searched for variants in non-disease-causing genes whose pLI was above 0.9 (ExAC Consortium data), in which truncating variants were found in at least 3 unrelated patients, in order to identity novel MH-ID genes. Only DLG4 gene met these criteria. Data from the literature and various databases also indicated its implication in ID. DLG4 encodes PSD-95, a protein expressed in various tissues including the brain. In neurons, PSD-95 is localized at the post-synaptic density, and is associated with glutamatergic receptor signaling (NMDA and AMPA). PSD-95 probably participates in dendritogenesis. Two patients were heterozygous for de novo frameshift variants and one for a consensus splice site variant. Gene expression studies supported their pathogenicity through haploinsufficiency and loss-of-function. Patients showed mild-to-moderate ID, similar marfanoid features, including a long face, high arched palate, long and thin fingers, pectus excavatum, scoliosis and ophthalmological manifestations (nystagmus or strabismus). Our study emphasizes the role of DLG4 as a novel post-synaptic-associated gene involved in syndromic ID associated with MH.

PMID: 29460436 [PubMed - as supplied by publisher]

Whole-Exome Sequencing in Adults With Chronic Kidney Disease: A Pilot Study.

Ann Intern Med. 2018 Feb 20;168(4):308

Authors:

PMID: 29459969 [PubMed - in process]

Rare deleterious variants in GRHL3 are associated with human spina bifida.

Hum Mutat. 2017 Jun;38(6):716-724

Authors: Lemay P, De Marco P, Emond A, Spiegelman D, Dionne-Laporte A, Laurent S, Merello E, Accogli A, Rouleau GA, Capra V, Kibar Z

Abstract
Neural tube defects, including spina bifida, are among the most common birth defects caused by failure of neural tube closure during development. They have a complex etiology involving largely undetermined environmental and genetic factors. Previous studies in mouse models have implicated the transcription factor Grhl3 as an important factor in the pathogenesis of spina bifida. In the present study, we conducted a resequencing analysis of GRHL3 in a cohort of 233 familial and sporadic cases of spina bifida. We identified two novel truncating variants: one homozygous frameshift variant, p.Asp16Aspfs*10, in two affected siblings and one heterozygous intronic splicing variant, p.Ala318Glyfs*26. We also identified five missense variants, one of which was demonstrated to reduce the activation of gene targets in a luciferase reporter assay. With the previously identified p.Arg391Cys variant, eight variants were found in GRHL3. Comparison of the variant rate between our cohort and the ExAC database identified a significant enrichment of deleterious variants in GRHL3 in the whole gene and the transactivation region in spina bifida patients. These data provide strong evidence for a role of GRHL3 as a predisposing factor to spina bifida and will help dissect the complex etiology and pathogenic mechanisms of these malformations.

PMID: 28276201 [PubMed - indexed for MEDLINE]