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1.
Sci Rep ; 11(1): 764, 2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33436942

RESUMO

Marfan syndrome and related disorders are a group of heritable connective tissue disorders and share many clinical features that involve cardiovascular, skeletal, craniofacial, ocular, and cutaneous abnormalities. The majority of affected individuals have aortopathies associated with early mortality and morbidity. Implementation of targeted gene panel next-generation sequencing in these individuals is a powerful tool to obtain a genetic diagnosis. Here, we report on clinical and genetic spectrum of 53 families from India with a total of 83 patients who had a clinical diagnosis suggestive of Marfan syndrome or related disorders. We obtained a molecular diagnosis in 45/53 (85%) index patients, in which 36/53 (68%) had rare variants in FBN1 (Marfan syndrome; 63 patients in total), seven (13.3%) in TGFBR1/TGFBR2 (Loeys-Dietz syndrome; nine patients in total) and two patients (3.7%) in SKI (Shprintzen-Goldberg syndrome). 21 of 41 rare variants (51.2%) were novel. We did not detect a disease-associated variant in 8 (15%) index patients, and none of them met the Ghent Marfan diagnostic criteria. We found the homozygous FBN1 variant p.(Arg954His) in a boy with typical features of Marfan syndrome. Our study is the first reporting on the spectrum of variants in FBN1, TGFBR1, TGFBR2, and SKI in Indian individuals.

2.
Hum Mutat ; 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33502066

RESUMO

Given the genomic uniqueness, a local dataset is most desired for Indians, who are underrepresented in existing public databases. We hypothesize patients with rare monogenic disorders and their family members can provide a reliable source of common variants in the population. Exome sequencing (ES) data from families with rare Mendelian disorders was aggregated from five centers in India. The dataset was refined by excluding related individuals and removing the disease-causing variants (refined cohort). The efficiency of these datasets was assessed in a new set of 50 exomes against gnomAD and GenomeAsia. Our original cohort comprised 1455 individuals from 1207 families. The refined cohort had 836 unrelated individuals that retained 1,251,064 variants with 181125 population specific and 489618 common variants. The allele frequencies from our cohort helped to define 97609 rare variants in gnomAD and 44520 rare variants in GenomeAsia as common variants in our population. Our variant dataset provided additional 1.7% and 0.1% efficiency for prioritizing heterozygous and homozygous variants respectively for rare monogenic disorders. We observed additional 19 genes/human knockouts. We list carrier frequency for 142 recessive disorders. This is a large and useful resource of exonic variants for Indians. Despite limitations, datasets from patients are efficient tools for variant prioritization in a resource limited setting. This article is protected by copyright. All rights reserved.

3.
Am J Hum Genet ; 108(1): 8-15, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33417889

RESUMO

The delineation of disease entities is complex, yet recent advances in the molecular characterization of diseases provide opportunities to designate diseases in a biologically valid manner. Here, we have formalized an approach to the delineation of Mendelian genetic disorders that encompasses two distinct but inter-related concepts: (1) the gene that is mutated and (2) the phenotypic descriptor, preferably a recognizably distinct phenotype. We assert that only by a combinatorial or dyadic approach taking both of these attributes into account can a unitary, distinct genetic disorder be designated. We propose that all Mendelian disorders should be designated as "GENE-related phenotype descriptor" (e.g., "CFTR-related cystic fibrosis"). This approach to delineating and naming disorders reconciles the complexity of gene-to-phenotype relationships in a simple and clear manner yet communicates the complexity and nuance of these relationships.


Assuntos
Doenças Genéticas Inatas/diagnóstico , Doenças Genéticas Inatas/genética , Genômica/métodos , Fibrose Cística/diagnóstico , Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Genótipo , Humanos , Mutação/genética , Fenótipo
4.
Am J Hum Genet ; 108(1): 115-133, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33308444

RESUMO

Signal peptide-CUB-EGF domain-containing protein 3 (SCUBE3) is a member of a small family of multifunctional cell surface-anchored glycoproteins functioning as co-receptors for a variety of growth factors. Here we report that bi-allelic inactivating variants in SCUBE3 have pleiotropic consequences on development and cause a previously unrecognized syndromic disorder. Eighteen affected individuals from nine unrelated families showed a consistent phenotype characterized by reduced growth, skeletal features, distinctive craniofacial appearance, and dental anomalies. In vitro functional validation studies demonstrated a variable impact of disease-causing variants on transcript processing, protein secretion and function, and their dysregulating effect on bone morphogenetic protein (BMP) signaling. We show that SCUBE3 acts as a BMP2/BMP4 co-receptor, recruits the BMP receptor complexes into raft microdomains, and positively modulates signaling possibly by augmenting the specific interactions between BMPs and BMP type I receptors. Scube3-/- mice showed craniofacial and dental defects, reduced body size, and defective endochondral bone growth due to impaired BMP-mediated chondrogenesis and osteogenesis, recapitulating the human disorder. Our findings identify a human disease caused by defective function of a member of the SCUBE family, and link SCUBE3 to processes controlling growth, morphogenesis, and bone and teeth development through modulation of BMP signaling.


Assuntos
Osso e Ossos/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Deficiências do Desenvolvimento/metabolismo , Osteogênese/fisiologia , Transdução de Sinais/fisiologia , Animais , Proteína Morfogenética Óssea 2/metabolismo , Proteína Morfogenética Óssea 4/metabolismo , Proteínas Morfogenéticas Ósseas/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Células HEK293 , Células Hep G2 , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células MCF-7 , Masculino , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL
6.
Am J Med Genet A ; 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-33135300

RESUMO

3-M syndrome is a rare autosomal recessive disorder, characterized by short stature, characteristic facies and absence of microcephaly and intellectual disability. 3-M syndrome 2 (MIM# 612921) is caused by biallelic disease causing variants in OBSL1. In this study, we identified two probands from two families with homozygous, c.1534 + 5G > T and compound heterozygous variants, c.35dup and c.1273dup in OBSL1, respectively. We herein highlight the clinical and molecular findings of the first reported cases from Indian ethnicity.

7.
Am J Med Genet A ; 182(12): 2951-2958, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32990402

RESUMO

Waardenburg syndrome subtypes 1 and 3 are caused by pathogenic variants in PAX3. We investigated 12 individuals from four unrelated families clinically diagnosed with Waardenburg syndrome type 1/3. Novel pathogenic variants identified in PAX3 included single nucleotide variants (c.166C>T, c.829C>T), a 2-base pair deletion (c.366_367delAA) and a multi-exonic deletion. Two novel variants, c.166C>T and c.829C>T and a previously reported variant, c.256A>T in PAX3 were evaluated for their nuclear localization and ability to activate MITF promoter. The coexistence of two subtypes of Waardenburg syndrome with pathogenic variants in PAX3 and EDNRB was seen in one of the affected individuals. Multiple genetic diagnoses of Waardenburg syndrome type 3 and autosomal recessive deafness 1A was identified in an individual. We also review the phenotypic and genomic spectrum of individuals with PAX3-related Waardenburg syndrome reported in the literature.

8.
Am J Med Genet A ; 182(11): 2793-2796, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32783269

RESUMO

Roberts syndrome (also known as Roberts-SC phocomelia syndrome) is an autosomal recessive developmental disorder, characterized by pre- and postnatal growth retardation, limb malformations including bilateral symmetric tetraphocomelia or mesomelia, and craniofacial dysmorphism. Biallelic loss-of-function variants in ESCO2, which codes for establishment of sister chromatid cohesion N-acetyltransferase 2, cause Roberts syndrome. Phenotypic spectrum among patients is broad, challenging clinical diagnosis in mildly affected individuals. Here we report a 3-year-old boy with a mild phenotype of Roberts syndrome with bilateral elbow contractures, humeroradial synostosis, mild lower limb disparity, and facial dysmorphism. Trio whole-exome sequencing identified the novel biallelic splice variant c.1673+1G>A in ESCO2 in the patient. Aberrant ESCO2 pre-mRNA splicing, reduced relative ESCO2 mRNA amount, and characteristic cytogenetic defects, such as premature centromere separation, heterochromatin repulsion, and chromosome breaks, in patient cells strongly supported pathogenicity of the ESCO2 variant affecting one of the highly conserved guanine-thymine dinucleotide of the donor splice site. Our case highlights the difficulty in establishing a clinical diagnosis in individuals with minor clinical features of Roberts syndrome and normal intellectual and social development. However, next-generation sequencing tools allow for molecular diagnosis in cases presenting with mild developmental defects.

9.
J Hum Genet ; 65(11): 971-984, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32651481

RESUMO

Mucolipidosis (ML) (OMIM 607840 & 607838) is a rare autosomal recessive inherited disorder that occurs due to the deficiency of golgi enzyme uridine diphosphate (UDP)- N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) responsible for tagging mannose-6-phosphate for proper trafficking of lysosomal enzymes to lysosomes. Variants in GlcNAc-phosphotransferase (GNPTAB (α, ß subunits) and GNPTG (γ subunits) are known to result in impaired targeting of lysosomal enzymes leading to Mucolipidosis (ML) Type II or Type III. We analyzed 69 Indian families of MLII/III for clinical features and molecular spectrum and performed in silico analysis for novel variants. We identified 38 pathogenic variants in GNPTAB and 5 pathogenic variants in GNPTG genes including missense, frame shift, deletion, duplication and splice site variations. A total of 26 novel variants were identified in GNPTAB and 4 in GNPTG gene. In silico studies using mutation prediction software like SIFT, Polyphen2 and protein structure analysis further confirmed the pathogenic nature of the novel sequence variants detected in our study. Except for a common variant c.3503_3504delTC in early onset MLII, we could not establish any other significant genotype and phenotype correlation. This is one of the largest studies reported till date on Mucolipidosis II/III in order to identify mutation spectrum and any recurrent mutations specific to the Indian ethnic population. The mutational spectrum information in Indian patients will be useful in better genetic counselling, carrier detection and prenatal diagnosis for patients with ML II/III.

10.
Am J Hum Genet ; 107(2): 293-310, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32707087

RESUMO

We identified ten persons in six consanguineous families with distal arthrogryposis (DA) who had congenital contractures, scoliosis, and short stature. Exome sequencing revealed that each affected person was homozygous for one of two different rare variants (c.470G>T [p.Cys157Phe] or c.469T>C [p.Cys157Arg]) affecting the same residue of myosin light chain, phosphorylatable, fast skeletal muscle (MYLPF). In a seventh family, a c.487G>A (p.Gly163Ser) variant in MYLPF arose de novo in a father, who transmitted it to his son. In an eighth family comprised of seven individuals with dominantly inherited DA, a c.98C>T (p.Ala33Val) variant segregated in all four persons tested. Variants in MYLPF underlie both dominant and recessively inherited DA. Mylpf protein models suggest that the residues associated with dominant DA interact with myosin whereas the residues altered in families with recessive DA only indirectly impair this interaction. Pathological and histological exam of a foot amputated from an affected child revealed complete absence of skeletal muscle (i.e., segmental amyoplasia). To investigate the mechanism for this finding, we generated an animal model for partial MYLPF impairment by knocking out zebrafish mylpfa. The mylpfa mutant had reduced trunk contractile force and complete pectoral fin paralysis, demonstrating that mylpf impairment most severely affects limb movement. mylpfa mutant muscle weakness was most pronounced in an appendicular muscle and was explained by reduced myosin activity and fiber degeneration. Collectively, our findings demonstrate that partial loss of MYLPF function can lead to congenital contractures, likely as a result of degeneration of skeletal muscle in the distal limb.


Assuntos
Artrogripose/genética , Músculo Esquelético/patologia , Anormalidades Musculoesqueléticas/genética , Mutação/genética , Cadeias Leves de Miosina/genética , Adolescente , Sequência de Aminoácidos , Animais , Criança , Contratura/genética , Extremidades/patologia , Feminino , Humanos , Masculino , Miosinas/genética , Linhagem , Adulto Jovem , Peixe-Zebra/genética
11.
Am J Hum Genet ; 107(1): 34-45, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32497488

RESUMO

IFAP syndrome is a rare genetic disorder characterized by ichthyosis follicularis, atrichia, and photophobia. Previous research found that mutations in MBTPS2, encoding site-2-protease (S2P), underlie X-linked IFAP syndrome. The present report describes the identification via whole-exome sequencing of three heterozygous mutations in SREBF1 in 11 unrelated, ethnically diverse individuals with autosomal-dominant IFAP syndrome. SREBF1 encodes sterol regulatory element-binding protein 1 (SREBP1), which promotes the transcription of lipogenes involved in the biosynthesis of fatty acids and cholesterols. This process requires cleavage of SREBP1 by site-1-protease (S1P) and S2P and subsequent translocation into the nucleus where it binds to sterol regulatory elements (SRE). The three detected SREBF1 mutations caused substitution or deletion of residues 527, 528, and 530, which are crucial for S1P cleavage. In vitro investigation of SREBP1 variants demonstrated impaired S1P cleavage, which prohibited nuclear translocation of the transcriptionally active form of SREBP1. As a result, SREBP1 variants exhibited significantly lower transcriptional activity compared to the wild-type, as demonstrated via luciferase reporter assay. RNA sequencing of the scalp skin from IFAP-affected individuals revealed a dramatic reduction in transcript levels of low-density lipoprotein receptor (LDLR) and of keratin genes known to be expressed in the outer root sheath of hair follicles. An increased rate of in situ keratinocyte apoptosis, which might contribute to skin hyperkeratosis and hypotrichosis, was also detected in scalp samples from affected individuals. Together with previous research, the present findings suggest that SREBP signaling plays an essential role in epidermal differentiation, skin barrier formation, hair growth, and eye function.


Assuntos
Artrogripose/genética , Mutação/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Regulação da Expressão Gênica/genética , Humanos , Ceratose/genética , Masculino , Pessoa de Meia-Idade , Linhagem , Fenótipo , Adulto Jovem
12.
Clin Dysmorphol ; 29(3): 123-126, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32282352

RESUMO

15-Hydroxyprostaglandin dehydrogenase is NAD-dependent catalytic enzyme involved in prostaglandin biosynthesis pathway encoded by HPGD. The pathogenic variations in HPGD cause primary hypertrophic osteoarthropathy (PHO). The objective of the present study is to identify the genetic basis in patients with digital clubbing due to PHO. We performed detailed clinical and radiographic evaluation and exome sequencing in patients from three unrelated Indian families with PHO. Exome sequencing revealed two novel, c.34G>A (p.Gly12Ser) and c.313C>T (p.Gln105*) and a known variant, c.418G>C (p.Ala140Pro) in HPGD. Herein, we add three Indian families to HPGD mutation spectrum and review the literature on variants in this gene.

13.
Gene ; 729: 144229, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31706999

RESUMO

Nephronophthisis is an autosomal recessive disease characterized by cystic kidney disease with progression to end-stage kidney disease in children and adolescents with or without extra-renal involvement. It is caused by biallelic pathogenic variants in 19 genes including INVS that encodes a ciliary protein essential for renal development and left-right axis establishment. We report a child with bilateral enlarged, echogenic, polycystic kidneys with end-stage renal disease, anemia and metabolic acidosis caused by biallelic novel pathogenic variants, c.796 + 5G > A and c.1789C > T in INVS. We show that the variant, c.796 + 5G > A disrupts the canonical splicing and nonsense variant, c.1789C > T results in nonsense mediated decay.


Assuntos
Doenças Renais Císticas/genética , Fatores de Transcrição/genética , Pré-Escolar , Códon sem Sentido , Feminino , Frequência do Gene , Variação Genética , Homozigoto , Humanos , Doenças Renais Císticas/metabolismo , Mutação , Sítios de Splice de RNA , Processamento de RNA , Fatores de Transcrição/metabolismo
14.
Am J Med Genet A ; 182(2): 338-347, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31755234

RESUMO

The phenotypic spectrum of Type 2 collagenopathies ranges from lethal achondrogenesis Type 2 to milder osteoarthritis with mild chondrodysplasia. All of them are monoallelic except for the two recent reports showing that biallelic variants in COL2A1 can cause spondyloepiphyseal dysplasia congenita in two children. Here we report two additional families with homozygous variants, c.4135C>T (p.Arg1379Cys) and c.3190C>T (p.Arg1133Cys) in COL2A1 resulting in two distinct skeletal dysplasia phenotypes of intermediate severity. Though all six patients from four families exhibit a spondylo-epimetaphyseal dysplasia, they demonstrate a wide variation in severity of short stature and involvement of epiphyses, metaphyses, and vertebrae. We hypothesize that the variants are likely to be hypomorphic, given the underlying mechanisms of disease causation for known heterozygous variants in COL2A1. With this report, we provide further evidence to the existence of autosomal recessive Type 2 collagenopathy.

15.
Am J Med Genet A ; 182(2): 303-313, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31854143

RESUMO

Turner syndrome (TS) is a common multiple congenital anomaly syndrome resulting from complete or partial absence of the second X chromosome. In this study, we explore the phenotype of TS in diverse populations using clinical examination and facial analysis technology. Clinical data from 78 individuals and images from 108 individuals with TS from 19 different countries were analyzed. Individuals were grouped into categories of African descent (African), Asian, Latin American, Caucasian (European descent), and Middle Eastern. The most common phenotype features across all population groups were short stature (86%), cubitus valgus (76%), and low posterior hairline 70%. Two facial analysis technology experiments were conducted: TS versus general population and TS versus Noonan syndrome. Across all ethnicities, facial analysis was accurate in diagnosing TS from frontal facial images as measured by the area under the curve (AUC). An AUC of 0.903 (p < .001) was found for TS versus general population controls and 0.925 (p < .001) for TS versus individuals with Noonan syndrome. In summary, we present consistent clinical findings from global populations with TS and additionally demonstrate that facial analysis technology can accurately distinguish TS from the general population and Noonan syndrome.

16.
Am J Med Genet A ; 182(4): 804-807, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31880392

RESUMO

Fetal akinesia deformation sequence (FADS) is a clinically and genetically heterogeneous condition. Pathogenic variants in DOK7 are known to cause myasthenic syndrome, congenital, 10 (MIM#254300) and, rarely (reported in a single family) lethal FADS. Herein, we describe a biallelic variant c.1263dupC in DOK7, known to cause congenital myasthenic syndrome 10, causing lethal FADS in a consanguineous family. The present report illustrates wide phenotypic variability caused by biallelic pathogenic variants in DOK7. We also describe the second family with FADS due to pathogenic variants in DOK7.

18.
Am J Med Genet A ; 182(1): 183-188, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31670473

RESUMO

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are RNA binding proteins, which aid in maturation, stabilization, and transport of mRNA. They have a significant role in cellular nucleic acid metabolism. The hnRNPs alter gene expression and are linked to various neurodegenerative disorders and cancers. Previously, six unrelated girls with developmental delay, intellectual disability, and hypotonia were found to have de novo heterozygous pathogenic missense variants in HNRNPH2, located on the X chromosome. A gain-of-function effect was proposed for the variant and it was thought to be lethal in males as no surviving males were identified. We describe a family with two affected siblings, one male and one female, with a known pathogenic variant in HNRNPH2, possibly due to maternal germline mosaicism.

19.
Clin Genet ; 96(6): 560-565, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31411728

RESUMO

Meckel syndrome (MKS) is a perinatally lethal, genetically heterogeneous, autosomal recessive condition caused by defective primary cilium formation leading to polydactyly, multiple cysts in kidneys and malformations of nervous system. We performed exome sequencing in six fetuses from six unrelated families with MKS. We identified seven novel variants in B9D2, TNXDC15, CC2D2A, CEP290 and TMEM67. We describe the second family with MKS due to a homozygous variant in B9D2 and fifth family with bi-allelic variant in TXNDC15. Our data validates the causation of MKS by pathogenic variation in B9D2 and TXNDC15 and also adds novel variants in CC2D2A, CEP290 and TMEM67 to the literature.


Assuntos
Transtornos da Motilidade Ciliar/genética , Transtornos da Motilidade Ciliar/patologia , Encefalocele/genética , Encefalocele/patologia , Feto/anormalidades , Mutação/genética , Doenças Renais Policísticas/genética , Doenças Renais Policísticas/patologia , Retinite Pigmentosa/genética , Retinite Pigmentosa/patologia , Sequência de Aminoácidos , Sequência de Bases , Segregação de Cromossomos/genética , Transtornos da Motilidade Ciliar/diagnóstico por imagem , Estudos de Coortes , Encefalocele/diagnóstico por imagem , Feminino , Humanos , Masculino , Linhagem , Fenótipo , Doenças Renais Policísticas/diagnóstico por imagem , Retinite Pigmentosa/diagnóstico por imagem
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