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1.
Genet Med ; 21(11): 2453-2461, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30992551

RESUMO

PURPOSE: Maternal diabetes is a known teratogen that can cause a wide spectrum of birth defects, collectively referred to as diabetic embryopathy (DE). However, the pathogenic mechanisms underlying DE remain uncertain and there are no definitive tests to establish the diagnosis. Here, we explore the potential of DNA methylation as a diagnostic biomarker for DE and to inform disease pathogenesis. METHODS: Bisulfite sequencing was used to identify gene regions with differential methylation between DE neonates and healthy infants born with or without prenatal exposure to maternal diabetes, and to investigate the role of allele-specific methylation at implicated sites. RESULTS: We identified a methylation signature consisting of 237 differentially methylated loci that distinguished infants with DE from control infants. These loci were found proximal to genes associated with Mendelian syndromes that overlap the DE phenotype (e.g., CACNA1C, TRIO, ANKRD11) or genes known to influence embryonic development (e.g., BRAX1, RASA3). Further, we identified allele-specific methylation (ASM) at 11 of these loci, within which 61.5% of ASM single-nucleotide variants are known expression quantitative trait loci (eQTLs). CONCLUSIONS: Our study suggests a role for aberrant DNA methylation and cis-sequence variation in the pathogenesis of DE and highlights the diagnostic potential of DNA methylation for teratogenic birth defects.

2.
Genome Med ; 11(1): 25, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31014393

RESUMO

BACKGROUND: Intrachromosomal triplications (TRP) can contribute to disease etiology via gene dosage effects, gene disruption, position effects, or fusion gene formation. Recently, post-zygotic de novo triplications adjacent to copy-number neutral genomic intervals with runs of homozygosity (ROH) have been shown to result in uniparental isodisomy (UPD). The genomic structure of these complex genomic rearrangements (CGRs) shows a consistent pattern of an inverted triplication flanked by duplications (DUP-TRP/INV-DUP) formed by an iterative DNA replisome template-switching mechanism during replicative repair of a single-ended, double-stranded DNA (seDNA), the ROH results from an interhomolog or nonsister chromatid template switch. It has been postulated that these CGRs may lead to genetic abnormalities in carriers due to dosage-sensitive genes mapping within the copy-number variant regions, homozygosity for alleles at a locus causing an autosomal recessive (AR) disease trait within the ROH region, or imprinting-associated diseases. METHODS: Here, we report a family wherein the affected subject carries a de novo 2.2-Mb TRP followed by 42.2 Mb of ROH and manifests clinical features overlapping with those observed in association with chromosome 14 maternal UPD (UPD(14)mat). UPD(14)mat can cause clinical phenotypic features enabling a diagnosis of Temple syndrome. This CGR was then molecularly characterized by high-density custom aCGH, genome-wide single-nucleotide polymorphism (SNP) and methylation arrays, exome sequencing (ES), and the Oxford Nanopore long-read sequencing technology. RESULTS: We confirmed the postulated DUP-TRP/INV-DUP structure by multiple orthogonal genomic technologies in the proband. The methylation status of known differentially methylated regions (DMRs) on chromosome 14 revealed that the subject shows the typical methylation pattern of UPD(14)mat. Consistent with these molecular findings, the clinical features overlap with those observed in Temple syndrome, including speech delay. CONCLUSIONS: These data provide experimental evidence that, in humans, triplication can lead to segmental UPD and imprinting disease. Importantly, genotype/phenotype analyses further reveal how a post-zygotically generated complex structural variant, resulting from a replication-based mutational mechanism, contributes to expanding the clinical phenotype of known genetic syndromes. Mechanistically, such events can distort transmission genetics resulting in homozygosity at a locus for which only one parent is a carrier as well as cause imprinting diseases.

3.
Genet Med ; 21(9): 2161, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30760893

RESUMO

This Article was originally published under Nature Research's License to Publish, but has now been made available under a [CC BY-NC-ND 4.0] license. The PDF and HTML versions of the Article have been modified accordingly.

4.
Eur J Hum Genet ; 27(4): 563-573, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30622330

RESUMO

Aberrant left-right patterning in the developing human embryo can lead to a broad spectrum of congenital malformations. The causes of most laterality defects are not known, with variants in established genes accounting for <20% of cases. We sought to characterize the genetic spectrum of these conditions by performing whole-exome sequencing of 323 unrelated laterality cases. We investigated the role of rare, predicted-damaging variation in 1726 putative laterality candidate genes derived from model organisms, pathway analyses, and human phenotypes. We also evaluated the contribution of homo/hemizygous exon deletions and gene-based burden of rare variation. A total of 28 candidate variants (26 rare predicted-damaging variants and 2 hemizygous deletions) were identified, including variants in genes known to cause heterotaxy and primary ciliary dyskinesia (ACVR2B, NODAL, ZIC3, DNAI1, DNAH5, HYDIN, MMP21), and genes without a human phenotype association, but with prior evidence for a role in embryonic laterality or cardiac development. Sanger validation of the latter variants in probands and their parents revealed no de novo variants, but apparent transmitted heterozygous (ROCK2, ISL1, SMAD2), and hemizygous (RAI2, RIPPLY1) variant patterns. Collectively, these variants account for 7.1% of our study subjects. We also observe evidence for an excess burden of rare, predicted loss-of-function variation in PXDNL and BMS1- two genes relevant to the broader laterality phenotype. These findings highlight potential new genes in the development of laterality defects, and suggest extensive locus heterogeneity and complex genetic models in this class of birth defects.

5.
Am J Med Genet A ; 179(3): 475-479, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30569621

RESUMO

Genetic alterations leading to overactivation of mammalian target of rapamycin (mTOR) signaling result in brain overgrowth syndromes such as focal cortical dysplasia (FCD) and megalencephaly. Megalencephaly with cutis tri-color of the Blaschko-linear type pigmentary mosaicism and intellectual disability is a rare neurodevelopmental disorder attributed to the recurrent mosaic c.5930C > T (p.Thr1977Ile) MTOR variant. This variant was previously reported at low to intermediate levels of mosaicism in the peripheral blood of three unrelated individuals with consistent clinical findings. We report a fourth case of a 3-year-old female presenting with megalencephaly, obstructive hydrocephalus due to cerebral aqueductal stenosis, asymmetric polymicrogyria, dysgenesis of the corpus callosum, hypotonia, developmental delay, and cutaneous pigmentary mosaicism. Oligonucleotide and SNP chromosomal microarray (CMA), karyotype, and trio whole exome sequencing (WES) in the peripheral blood, as well as a targeted gene variant panel from fibroblasts derived from hyperpigmented and non-hyperpigmented skin did not detect any abnormalities in MTOR or other genes associated with brain overgrowth syndromes. Unlike the previously reported cases, the de novo c.5930C > T (p.Thr1977Ile) MTOR variant was detected at 32% mosaicism in our patient only after WES was performed on fibroblast-derived DNA from the hyperpigmented skin. This case demonstrates the tissue variability in mosaic expression of the recurrent p.Thr1977Ile MTOR variant, emphasizes the need for skin biopsies in the genetic evaluation of patients with skin pigmentary mosaicism, and expands the clinical phenotype associated with this pathogenic MTOR variant.

6.
Genet Med ; 21(7): 1652-1656, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30568308

RESUMO

PURPOSE: Brain malformations caused by 17p13.3 deletions include lissencephaly with deletions of the larger Miller-Dieker syndrome region or smaller deletions of only PAFAH1B1, white matter changes, and a distinct syndrome due to deletions including YWHAE and CRK but sparing PAFAH1B1. We sought to understand the significance of 17p13.3 deletions between the YWHAE/CRK and PAFAH1B1 loci. METHODS: We analyzed the clinical features of six individuals from five families with 17p13.3 deletions between and not including YWHAE/CRK and PAFAH1B1 identified among individuals undergoing clinical chromosomal microarray testing or research genome sequencing. RESULTS: Five individuals from four families had multifocal white matter lesions while a sixth had a normal magnetic resonance image. A combination of our individuals and a review of those in the literature with white matter changes and deletions in this chromosomal region narrows the overlapping region for this brain phenotype to ~345 kb, including 11 RefSeq genes, with RTN4RL1 haploinsufficiency as the best candidate for causing this phenotype. CONCLUSION: While previous literature has hypothesized dysmorphic features and white matter changes related to YWHAE, our cohort contributes evidence to the presence of additional genetic changes within 17p13.3 required for proper brain development.

7.
Genet Med ; 21(8): 1781-1789, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-30568310

RESUMO

PURPOSE: To identify the economic impact of pediatric patients with clinical indications of genetic disease (GD) on the US health-care system. METHODS: Using the 2012 Kids' Inpatient Database, we identified pediatric inpatient discharges with International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes linked to genetic disease, including well-established genetic disorders, neurological diseases, birth defects, and other physiological or functional abnormalities with a genetic basis. Cohort characteristics and health-care utilization measures were analyzed. Discharges with a GD-associated primary diagnosis were used to estimate the minimum burden; discharges with GD-associated primary or secondary codes established the maximum burden. RESULTS: Of 5.85 million weighted discharges, 2.6-14% included GD-associated ICD-9-CM codes. For these discharges, mean total costs were $16,000-77,000 higher (P < 0.0001) in neonates and $12,000-17,000 higher (P < 0.0001) in pediatric patients compared with background, corresponding to significantly higher total charges and lengths of stay. Aggregate total charges for suspected GD accounted for $14 to $57 billion (11-46%) of the "national bill" for pediatric patients in 2012. CONCLUSION: Pediatric inpatients with diagnostic codes linked to genetic disease have a significant and disproportionate impact on resources and costs in the US health-care system.

8.
Artigo em Inglês | MEDLINE | ID: mdl-30382603

RESUMO

Because survivors of pediatric acute lymphoblastic leukemia (ALL) are more likely to be obese than unaffected contemporaries, we compared DNA methylation profiles between normal-weight and obese survivors at adiposity-associated CpG sites previously-reported by epigenome-wide association studies (EWAS) of body mass index (BMI) in the general population. We selected 96 ALL survivors from the Childhood Cancer Survivor Study: 48 obese and 48 normal weight. The Illumina HumanMethylation450 BeadChip was used to compare DNA methylation at 211 loci identified in EWAS of BMI in the general population. Thirty-nine loci were associated (false discovery rate <0.05) with obesity among survivors who only received chemotherapy (n = 49). No loci were significantly associated with obesity among CRT-exposed survivors (n = 47). Our results suggest that previously identified BMI-DNA methylation loci are associated with obesity in ALL survivors who were spared CRT, while no loci were significantly associated with obesity in survivors who received CRT.

9.
Ann Clin Transl Neurol ; 5(10): 1277-1285, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30349862

RESUMO

De novo variants in DDX3X account for 1-3% of unexplained intellectual disability (ID) cases and are amongst the most common causes of ID especially in females. Forty-seven patients (44 females, 3 males) have been described. We identified 31 additional individuals carrying 29 unique DDX3X variants, including 30 postnatal individuals with complex clinical presentations of developmental delay or ID, and one fetus with abnormal ultrasound findings. Rare or novel phenotypes observed include respiratory problems, congenital heart disease, skeletal muscle mitochondrial DNA depletion, and late-onset neurologic decline. Our findings expand the spectrum of DNA variants and phenotypes associated with DDX3X disorders.

10.
Eur J Hum Genet ; 26(9): 1294-1305, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29748569

RESUMO

The NAA10-NAA15 complex (NatA) is an N-terminal acetyltransferase that catalyzes N-terminal acetylation of ~40% of all human proteins. N-terminal acetylation has several different roles in the cell, including altering protein stability and degradation, protein localization and protein-protein interactions. In recent years several X-linked NAA10 variants have been associated with genetic disorders. We have identified a previously undescribed NAA10 c.215T>C p.(Ile72Thr) variant in three boys from two unrelated families with a milder phenotypic spectrum in comparison to most of the previously described patients with NAA10 variants. These boys have development delay, intellectual disability, and cardiac abnormalities as overlapping phenotypes. Functional studies reveal that NAA10 Ile72Thr is destabilized, while binding to NAA15 most likely is intact. Surprisingly, the NatA activity of NAA10 Ile72Thr appears normal while its monomeric activity is decreased. This study further broadens the phenotypic spectrum associated with NAA10 deficiency, and adds to the evidence that genotype-phenotype correlations for NAA10 variants are much more complex than initially anticipated.

11.
Genome Med ; 9(1): 95, 2017 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-29089047

RESUMO

BACKGROUND: Left-sided lesions (LSLs) account for an important fraction of severe congenital cardiovascular malformations (CVMs). The genetic contributions to LSLs are complex, and the mutations that cause these malformations span several diverse biological signaling pathways: TGFB, NOTCH, SHH, and more. Here, we use whole exome sequence data generated in 342 LSL cases to identify likely damaging variants in putative candidate CVM genes. METHODS: Using a series of bioinformatics filters, we focused on genes harboring population-rare, putative loss-of-function (LOF), and predicted damaging variants in 1760 CVM candidate genes constructed a priori from the literature and model organism databases. Gene variants that were not observed in a comparably sequenced control dataset of 5492 samples without severe CVM were then subjected to targeted validation in cases and parents. Whole exome sequencing data from 4593 individuals referred for clinical sequencing were used to bolster evidence for the role of candidate genes in CVMs and LSLs. RESULTS: Our analyses revealed 28 candidate variants in 27 genes, including 17 genes not previously associated with a human CVM disorder, and revealed diverse patterns of inheritance among LOF carriers, including 9 confirmed de novo variants in both novel and newly described human CVM candidate genes (ACVR1, JARID2, NR2F2, PLRG1, SMURF1) as well as established syndromic CVM genes (KMT2D, NF1, TBX20, ZEB2). We also identified two genes (DNAH5, OFD1) with evidence of recessive and hemizygous inheritance patterns, respectively. Within our clinical cohort, we also observed heterozygous LOF variants in JARID2 and SMAD1 in individuals with cardiac phenotypes, and collectively, carriers of LOF variants in our candidate genes had a four times higher odds of having CVM (odds ratio = 4.0, 95% confidence interval 2.5-6.5). CONCLUSIONS: Our analytical strategy highlights the utility of bioinformatic resources, including human disease records and model organism phenotyping, in novel gene discovery for rare human disease. The results underscore the extensive genetic heterogeneity underlying non-syndromic LSLs, and posit potential novel candidate genes and complex modes of inheritance in this important group of birth defects.


Assuntos
Cardiopatias Congênitas/genética , Feminino , Heterogeneidade Genética , Humanos , Padrões de Herança , Masculino , Sequenciamento Completo do Exoma
12.
JAMA Pediatr ; 171(12): e173438, 2017 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-28973083

RESUMO

Importance: While congenital malformations and genetic diseases are a leading cause of early infant death, to our knowledge, the contribution of single-gene disorders in this group is undetermined. Objective: To determine the diagnostic yield and use of clinical exome sequencing in critically ill infants. Design, Setting, and Participants: Clinical exome sequencing was performed for 278 unrelated infants within the first 100 days of life who were admitted to Texas Children's Hospital in Houston, Texas, during a 5-year period between December 2011 and January 2017. Exome sequencing types included proband exome, trio exome, and critical trio exome, a rapid genomic assay for seriously ill infants. Main Outcomes and Measures: Indications for testing, diagnostic yield of clinical exome sequencing, turnaround time, molecular findings, patient age at diagnosis, and effect on medical management among a group of critically ill infants who were suspected to have genetic disorders. Results: The mean (SEM) age for infants participating in the study was 28.5 (1.7) days; of these, the mean (SEM) age was 29.0 (2.2) days for infants undergoing proband exome sequencing, 31.5 (3.9) days for trio exome, and 22.7 (3.9) days for critical trio exome. Clinical indications for exome sequencing included a range of medical concerns. Overall, a molecular diagnosis was achieved in 102 infants (36.7%) by clinical exome sequencing, with relatively low yield for cardiovascular abnormalities. The diagnosis affected medical management for 53 infants (52.0%) and had a substantial effect on informed redirection of care, initiation of new subspecialist care, medication/dietary modifications, and furthering life-saving procedures in select patients. Critical trio exome sequencing revealed a molecular diagnosis in 32 of 63 infants (50.8%) at a mean (SEM) of 33.1 (5.6) days of life with a mean (SEM) turnaround time of 13.0 (0.4) days. Clinical care was altered by the diagnosis in 23 of 32 patients (71.9%). The diagnostic yield, patient age at diagnosis, and medical effect in the group that underwent critical trio exome sequencing were significantly different compared with the group who underwent regular exome testing. For deceased infants (n = 81), genetic disorders were molecularly diagnosed in 39 (48.1%) by exome sequencing, with implications for recurrence risk counseling. Conclusions and Relevance: Exome sequencing is a powerful tool for the diagnostic evaluation of critically ill infants with suspected monogenic disorders in the neonatal and pediatric intensive care units and its use has a notable effect on clinical decision making.


Assuntos
Doenças Genéticas Inatas/diagnóstico , Unidades de Terapia Intensiva Pediátrica , Sequenciamento Completo do Exoma/métodos , Adulto , Cuidados Críticos/métodos , Gerenciamento Clínico , Exoma , Aconselhamento Genético/métodos , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/terapia , Humanos , Lactente , Cuidado do Lactente/métodos , Recém-Nascido , Tempo de Internação/estatística & dados numéricos , Estudos Retrospectivos , Texas
14.
Genome Med ; 9(1): 73, 2017 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-28807008

RESUMO

BACKGROUND: De novo missense variants in CDK13 have been described as the cause of syndromic congenital heart defects in seven individuals ascertained from a large congenital cardiovascular malformations cohort. We aimed to further define the phenotypic and molecular spectrum of this newly described disorder. METHODS: To minimise ascertainment bias, we recruited nine additional individuals with CDK13 pathogenic variants from clinical and research exome laboratory sequencing cohorts. Each individual underwent dysmorphology exam and comprehensive medical history review. RESULTS: We demonstrate greater than expected phenotypic heterogeneity, including 33% (3/9) of individuals without structural heart disease on echocardiogram. There was a high penetrance for a unique constellation of facial dysmorphism and global developmental delay, as well as less frequently seen renal and sacral anomalies. Two individuals had novel CDK13 variants (p.Asn842Asp, p.Lys734Glu), while the remaining seven unrelated individuals had a recurrent, previously published p.Asn842Ser variant. Summary of all variants published to date demonstrates apparent restriction of pathogenic variants to the protein kinase domain with clustering in the ATP and magnesium binding sites. CONCLUSIONS: Here we provide detailed phenotypic and molecular characterisation of individuals with pathogenic variants in CDK13 and propose management guidelines based upon the estimated prevalence of anomalies identified.


Assuntos
Proteína Quinase CDC2/genética , Face/anormalidades , Cardiopatias Congênitas/metabolismo , Deficiência Intelectual/metabolismo , Mutação , Fenótipo , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Cardiopatias Congênitas/genética , Humanos , Lactente , Deficiência Intelectual/genética , Masculino , Síndrome
15.
Am J Med Genet A ; 173(8): 2176-2188, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28653806

RESUMO

Congenital left-sided cardiac lesions (LSLs) are a significant contributor to the mortality and morbidity of congenital heart disease (CHD). Structural copy number variants (CNVs) have been implicated in LSL without extra-cardiac features; however, non-penetrance and variable expressivity have created uncertainty over the use of CNV analyses in such patients. High-density SNP microarray genotyping data were used to infer large, likely-pathogenic, autosomal CNVs in a cohort of 1,139 probands with LSL and their families. CNVs were molecularly confirmed and the medical records of individual carriers reviewed. The gene content of novel CNVs was then compared with public CNV data from CHD patients. Large CNVs (>1 MB) were observed in 33 probands (∼3%). Six of these were de novo and 14 were not observed in the only available parent sample. Associated cardiac phenotypes spanned a broad spectrum without clear predilection. Candidate CNVs were largely non-recurrent, associated with heterozygous loss of copy number, and overlapped known CHD genomic regions. Novel CNV regions were enriched for cardiac development genes, including seven that have not been previously associated with human CHD. CNV analysis can be a clinically useful and molecularly informative tool in LSLs without obvious extra-cardiac defects, and may identify a clinically relevant genomic disorder in a small but important proportion of these individuals.


Assuntos
Variações do Número de Cópias de DNA/genética , Cardiopatias Congênitas/genética , Coração/fisiopatologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Estudos de Associação Genética , Genômica , Genótipo , Cardiopatias Congênitas/fisiopatologia , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Fenótipo , Polimorfismo de Nucleotídeo Único , Adulto Jovem
16.
Genome Med ; 9(1): 26, 2017 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-28327206

RESUMO

BACKGROUND: Given the rarity of most single-gene Mendelian disorders, concerted efforts of data exchange between clinical and scientific communities are critical to optimize molecular diagnosis and novel disease gene discovery. METHODS: We designed and implemented protocols for the study of cases for which a plausible molecular diagnosis was not achieved in a clinical genomics diagnostic laboratory (i.e. unsolved clinical exomes). Such cases were recruited to a research laboratory for further analyses, in order to potentially: (1) accelerate novel disease gene discovery; (2) increase the molecular diagnostic yield of whole exome sequencing (WES); and (3) gain insight into the genetic mechanisms of disease. Pilot project data included 74 families, consisting mostly of parent-offspring trios. Analyses performed on a research basis employed both WES from additional family members and complementary bioinformatics approaches and protocols. RESULTS: Analysis of all possible modes of Mendelian inheritance, focusing on both single nucleotide variants (SNV) and copy number variant (CNV) alleles, yielded a likely contributory variant in 36% (27/74) of cases. If one includes candidate genes with variants identified within a single family, a potential contributory variant was identified in a total of ~51% (38/74) of cases enrolled in this pilot study. The molecular diagnosis was achieved in 30/63 trios (47.6%). Besides this, the analysis workflow yielded evidence for pathogenic variants in disease-associated genes in 4/6 singleton cases (66.6%), 1/1 multiplex family involving three affected siblings, and 3/4 (75%) quartet families. Both the analytical pipeline and the collaborative efforts between the diagnostic and research laboratories provided insights that allowed recent disease gene discoveries (PURA, TANGO2, EMC1, GNB5, ATAD3A, and MIPEP) and increased the number of novel genes, defined in this study as genes identified in more than one family (DHX30 and EBF3). CONCLUSION: An efficient genomics pipeline in which clinical sequencing in a diagnostic laboratory is followed by the detailed reanalysis of unsolved cases in a research environment, supplemented with WES data from additional family members, and subject to adjuvant bioinformatics analyses including relaxed variant filtering parameters in informatics pipelines, can enhance the molecular diagnostic yield and provide mechanistic insights into Mendelian disorders. Implementing these approaches requires collaborative clinical molecular diagnostic and research efforts.


Assuntos
Biologia Computacional/métodos , Variações do Número de Cópias de DNA , Doenças Genéticas Inatas/diagnóstico , Genômica/métodos , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA/métodos , ATPases Associadas a Diversas Atividades Celulares , Adenosina Trifosfatases/genética , Proteínas de Ligação a DNA/genética , Exoma , Feminino , Subunidades beta da Proteína de Ligação ao GTP/genética , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/metabolismo , Humanos , Masculino , Proteínas de Membrana/genética , Metaloendopeptidases/genética , Proteínas Mitocondriais/genética , Projetos Piloto , Fatores de Transcrição/genética
17.
Cold Spring Harb Mol Case Stud ; 3(2): a000984, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28299356

RESUMO

Moebius syndrome is characterized by congenital unilateral or bilateral facial and abducens nerve palsies (sixth and seventh cranial nerves) causing facial weakness, feeding difficulties, and restricted ocular movements. Abnormalities of the chest wall such as Poland anomaly and variable limb defects are frequently associated with this syndrome. Most cases are isolated; however, rare families with autosomal dominant transmission with incomplete penetrance and variable expressivity have been described. The genetic basis of this condition remains unknown. In a cohort study of nine individuals suspected to have Moebius syndrome (six typical, three atypical), we performed whole-exome sequencing to try to identify a commonly mutated gene. Although no such gene was identified and we did not find mutations in PLXND1 and REV3L, we found a de novo heterozygous mutation, p.E410K, in the gene encoding tubulin beta 3 class III (TUBB3), in an individual with atypical Moebius syndrome. This individual was diagnosed with near-complete ophthalmoplegia, agenesis of the corpus callosum, and absence of the septum pellucidum. No substantial limb abnormalities were noted. Mutations in TUBB3 have been associated with complex cortical dysplasia and other brain malformations and congenital fibrosis of extraocular muscles type 3A (CFEOM3A). Our report highlights the overlap of genetic etiology and clinical differences between CFEOM and Moebius syndrome and describes our approach to identifying candidate genes for typical and atypical Moebius syndrome.


Assuntos
Síndrome de Möbius/genética , Tubulina (Proteína)/genética , Criança , Pré-Escolar , Estudos de Coortes , Exoma , Oftalmopatias Hereditárias/genética , Paralisia Facial/congênito , Paralisia Facial/genética , Feminino , Humanos , Lactente , Masculino , Malformações do Desenvolvimento Cortical/genética , Doenças Musculares/genética , Mutação , Transtornos da Motilidade Ocular/genética , Oftalmoplegia/genética , Doenças Orbitárias/genética , Linhagem , Tubulina (Proteína)/metabolismo , Sequenciamento Completo do Exoma
18.
Nucleic Acids Res ; 45(4): 1633-1648, 2017 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-27980096

RESUMO

We developed an algorithm, HMZDelFinder, that uses whole exome sequencing (WES) data to identify rare and intragenic homozygous and hemizygous (HMZ) deletions that may represent complete loss-of-function of the indicated gene. HMZDelFinder was applied to 4866 samples in the Baylor-Hopkins Center for Mendelian Genomics (BHCMG) cohort and detected 773 HMZ deletion calls (567 homozygous or 206 hemizygous) with an estimated sensitivity of 86.5% (82% for single-exonic and 88% for multi-exonic calls) and precision of 78% (53% single-exonic and 96% for multi-exonic calls). Out of 773 HMZDelFinder-detected deletion calls, 82 were subjected to array comparative genomic hybridization (aCGH) and/or breakpoint PCR and 64 were confirmed. These include 18 single-exon deletions out of which 8 were exclusively detected by HMZDelFinder and not by any of seven other CNV detection tools examined. Further investigation of the 64 validated deletion calls revealed at least 15 pathogenic HMZ deletions. Of those, 7 accounted for 17-50% of pathogenic CNVs in different disease cohorts where 7.1-11% of the molecular diagnosis solved rate was attributed to CNVs. In summary, we present an algorithm to detect rare, intragenic, single-exon deletion CNVs using WES data; this tool can be useful for disease gene discovery efforts and clinical WES analyses.


Assuntos
Biologia Computacional/métodos , Variações do Número de Cópias de DNA , Exoma , Doenças Genéticas Inatas/genética , Hemizigoto , Sequenciamento de Nucleotídeos em Larga Escala , Homozigoto , Algoritmos , Processamento Alternativo , Estudos de Coortes , Consanguinidade , Conjuntos de Dados como Assunto , Doenças Genéticas Inatas/diagnóstico , Humanos , Padrões de Herança , Modelos Genéticos , Linhagem , Reprodutibilidade dos Testes , Deleção de Sequência , Fluxo de Trabalho
19.
Genet Med ; 19(4): 412-420, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27657687

RESUMO

PURPOSE: To investigate the utility of whole-exome sequencing (WES) to define a molecular diagnosis for patients clinically diagnosed with congenital anomalies of kidney and urinary tract (CAKUT). METHODS: WES was performed in 62 families with CAKUT. WES data were analyzed for single-nucleotide variants (SNVs) in 35 known CAKUT genes, putatively deleterious sequence changes in new candidate genes, and potentially disease-associated copy-number variants (CNVs). RESULTS: In approximately 5% of families, pathogenic SNVs were identified in PAX2, HNF1B, and EYA1. Observed phenotypes in these families expand the current understanding about the role of these genes in CAKUT. Four pathogenic CNVs were also identified using two CNV detection tools. In addition, we found one deleterious de novo SNV in FOXP1 among the 62 families with CAKUT. The clinical database of the Baylor Miraca Genetics laboratory was queried and seven additional unrelated individuals with novel de novo SNVs in FOXP1 were identified. Six of these eight individuals with FOXP1 SNVs have syndromic urinary tract defects, implicating this gene in urinary tract development. CONCLUSION: We conclude that WES can be used to identify molecular etiology (SNVs, CNVs) in a subset of individuals with CAKUT. WES can also help identify novel CAKUT genes.Genet Med 19 4, 412-420.


Assuntos
Variações do Número de Cópias de DNA , Predisposição Genética para Doença/genética , Anormalidades Urogenitais/diagnóstico , Refluxo Vesicoureteral/diagnóstico , Sequenciamento Completo do Exoma/métodos , Adolescente , Criança , Pré-Escolar , Feminino , Fatores de Transcrição Forkhead/genética , Fator 1-beta Nuclear de Hepatócito/genética , Humanos , Lactente , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Proteínas Nucleares/genética , Fator de Transcrição PAX2/genética , Linhagem , Polimorfismo de Nucleotídeo Único , Proteínas Tirosina Fosfatases/genética , Proteínas Repressoras/genética , Anormalidades Urogenitais/genética , Refluxo Vesicoureteral/genética , Adulto Jovem
20.
J Allergy Clin Immunol ; 139(1): 232-245, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27577878

RESUMO

BACKGROUND: Primary immunodeficiency diseases (PIDDs) are clinically and genetically heterogeneous disorders thus far associated with mutations in more than 300 genes. The clinical phenotypes derived from distinct genotypes can overlap. Genetic etiology can be a prognostic indicator of disease severity and can influence treatment decisions. OBJECTIVE: We sought to investigate the ability of whole-exome screening methods to detect disease-causing variants in patients with PIDDs. METHODS: Patients with PIDDs from 278 families from 22 countries were investigated by using whole-exome sequencing. Computational copy number variant (CNV) prediction pipelines and an exome-tiling chromosomal microarray were also applied to identify intragenic CNVs. Analytic approaches initially focused on 475 known or candidate PIDD genes but were nonexclusive and further tailored based on clinical data, family history, and immunophenotyping. RESULTS: A likely molecular diagnosis was achieved in 110 (40%) unrelated probands. Clinical diagnosis was revised in about half (60/110) and management was directly altered in nearly a quarter (26/110) of families based on molecular findings. Twelve PIDD-causing CNVs were detected, including 7 smaller than 30 Kb that would not have been detected with conventional diagnostic CNV arrays. CONCLUSION: This high-throughput genomic approach enabled detection of disease-related variants in unexpected genes; permitted detection of low-grade constitutional, somatic, and revertant mosaicism; and provided evidence of a mutational burden in mixed PIDD immunophenotypes.


Assuntos
Síndromes de Imunodeficiência/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Variações do Número de Cópias de DNA , Feminino , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Adulto Jovem
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