RESUMO
Primitive epidermis develops the nail apparatus. Nails have a strong and inflexible nail plate at the end of each digit. Very few genes responsible for causing nonsyndromic form of nail dysplasia have been reported. In the current study, peripheral blood samples were collectedfrom three unaffected individuals and four affectedindividuals of Family A, while blood from two affected and three unaffected individuals were taken of Family B. Genotyping in both the families was performed using highly polymorphic short tandem repeat microsatellite markers. Sanger sequence of the FZD6 gene was performed and analysed for segregation analysis. A comparative modelling approach was used to predict the three-dimensional structures of FZD-6 protein using Modeller 4. Linkage analysis mapped a disease locus on chromosome 8q22.3, harbouring FZD6. Targeted Sanger sequencing of all the coding exons of FZD6 revealed a nonsense sequence variant in pedigree A, whereas a missense sequence variant in pedigree B. Finding and literature indicates the disease spectrum of Pakistani population with claw-shaped nail dysplasia, particularly in families of Pashtun origin.
Assuntos
Receptores Frizzled/genética , Genes Recessivos/genética , Mutação de Sentido Incorreto/genética , Doenças da Unha , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Doenças da Unha/genética , Doenças da Unha/patologia , Linhagem , Adulto JovemRESUMO
BACKGROUND: Genodermatoses represent genetic anomalies of skin tissues including hair follicles, sebaceous glands, eccrine glands, nails, and teeth. Ten consanguineous families segregating various genodermatosis phenotypes were investigated in the present study. METHODS: Homozygosity mapping, exome, and Sanger sequencing were employed to search for the disease-causing variants in the 10 families. RESULTS: Exome sequencing identified seven homozygous sequence variants in different families, including: c.27delT in FERMT1; c.836delA in ABHD5; c.2453C>T in ERCC5; c.5314C>T in COL7A1; c.1630C>T in ALOXE3; c.502C>T in PPOX; and c.10G>T in ALDH3A2. Sanger sequencing revealed three homozygous variants: c.1718 + 2A>G in FERMT1; c.10459A>T in FLG; and c.92delT in the KRT14 genes as the underlying genetic cause of skin phenotypes. CONCLUSION: This study supports the use of exome sequencing as a powerful, efficient tool for identifying genes that underlie rare monogenic skin disorders.
Assuntos
Doenças Raras/genética , Dermatopatias Genéticas/genética , 1-Acilglicerol-3-Fosfato O-Aciltransferase/genética , Aldeído Oxirredutases/genética , Vesícula/genética , Colágeno Tipo VII/genética , Consanguinidade , Análise Mutacional de DNA , Proteínas de Ligação a DNA/genética , Endonucleases/genética , Epidermólise Bolhosa/genética , Epidermólise Bolhosa Distrófica/genética , Epidermólise Bolhosa Simples/genética , Exoma , Feminino , Proteínas Filagrinas , Flavoproteínas/genética , Homozigoto , Humanos , Mutação INDEL , Eritrodermia Ictiosiforme Congênita/genética , Ictiose Vulgar/genética , Ictiose Lamelar/genética , Proteínas de Filamentos Intermediários/genética , Queratina-14/genética , Erros Inatos do Metabolismo Lipídico/genética , Lipoxigenase/genética , Masculino , Proteínas de Membrana/genética , Proteínas Mitocondriais/genética , Doenças Musculares/genética , Proteínas de Neoplasias/genética , Proteínas Nucleares/genética , Linhagem , Doenças Periodontais/genética , Fenótipo , Transtornos de Fotossensibilidade/genética , Porfiria Variegada/genética , Protoporfirinogênio Oxidase/genética , Síndrome de Sjogren-Larsson/genética , Fatores de Transcrição/genética , Xeroderma Pigmentoso/genéticaRESUMO
BackgroundOsteogenesis imperfecta (OI) is a heritable bone fragility disorder usually caused by dominant variants in COL1A1 or COL1A2 genes. Over the last few years, 17 genes including 12 autosomal recessive and five autosomal dominant forms of OI, involved in various aspects of bone formation, have been identified.MethodsWhole-exome sequencing followed by conventional Sanger sequencing was performed in a single affected individual (IV-3) in a family.ResultsHere, we report the clinical and genetic characterization of OI type 3 in a consanguineous family with four affected members. Clinical examinations revealed low bone density, short stature, severe vertebral compression fractures, and multiple long bone fractures in the affected members. Exome sequencing revealed a biallelic pathogenic splice acceptor site variant (c.359-3C>G) in a wingless-type mouse mammary tumor virus integration site family 1 (WNT1) gene located on chromosome 12q13.12.ConclusionWe report a biallelic splice site variant underlying OI type 3 and the first case from the Pakistani population.
Assuntos
Análise Mutacional de DNA/métodos , Sequenciamento do Exoma , Homozigoto , Mutação , Osteogênese Imperfeita/genética , Sítios de Splice de RNA , Proteína Wnt1/genética , Adolescente , Criança , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Hereditariedade , Humanos , Masculino , Osteogênese Imperfeita/complicações , Osteogênese Imperfeita/diagnóstico por imagem , Paquistão , Linhagem , FenótipoRESUMO
Ellis-van Creveld syndrome is an autosomal recessive skeletal dysplasia primarily characterized by the features such as disproportionate dwarfism, short ribs, short limbs, dysplastic nails, cardiovascular malformations, post-axial polydactyly (PAP) (bilateral) of hands and feet. EVC/EVC2 located in head-to-head arrangement on chromosome 4p16 are the causative genes for EvC syndrome. In the study, we present two families, A and B, with Pakistani and Republic of Kosovo origin, respectively. They showed features of EvC syndrome and were clinically and genetically characterized. In family A, the affected members showed an additional feature of profound deafness. The whole exome sequencing (WES) in this family revealed two homozygous variants in EVC2 (c.30dupC; p.Thr11Hisfs*45) and TMC1 (c.1696-1G>A) genes. In family B, WES revealed novel compound heterozygous variants (p.Ser307Pro, c.2894+3A>G) in the EVC gene. This study reports first case of variants in the genes causing EvC syndrome and profound deafness in the same family.
Assuntos
Síndrome de Ellis-Van Creveld/genética , Dedos/anormalidades , Proteínas de Membrana/genética , Polidactilia/genética , Proteínas/genética , Dedos do Pé/anormalidades , Adolescente , Criança , Pré-Escolar , Síndrome de Ellis-Van Creveld/fisiopatologia , Feminino , Dedos/fisiopatologia , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Masculino , Mutação , Linhagem , Fenótipo , Polidactilia/fisiopatologia , Dedos do Pé/fisiopatologia , Sequenciamento do ExomaRESUMO
Hypotrichosis is a condition of abnormal hair pattern characterized by sparse to absent hair on different parts of the body, including the scalp. The condition is often characterized by tightly curled woolly hairs, discoloration of hair, and development of multiple keratin filled cysts or papules on the body. Sequence analysis of the lipase H (LIPH) gene, mapped on chromosome 3q27.3, led to the identification of a novel frameshift deletion variant (c.932delC, p.Pro311Leufs*3) in one family and previously reported 2-bp deletion (c.659_660delTA) in five other families, inherited hypotrichosis, and woolly hair in an autosomal recessive pattern. The study further extends the body of evidence that sequence variants in the LIPH gene result in hypotrichosis and woolly hair phenotype.
Assuntos
Mutação da Fase de Leitura , Hipotricose/genética , Lipase/genética , Cromossomos Humanos Par 3/genética , Predisposição Genética para Doença , Variação Genética , Cabelo , Humanos , Fenótipo , Análise de Sequência de DNARESUMO
Alopecia with mental retardation (APMR) is a very rare disorder. In this study, we report on a consanguineous Pakistani family (AP91) with mild-to-moderate intellectual disability, adolescent alopecia and dentogingival abnormalities. Using homozygosity mapping, linkage analysis and exome sequencing, we identified a novel rare missense variant c.898G>A (p.(Glu300Lys)) in ITGB6, which co-segregates with the phenotype within the family and is predicted to be deleterious. Structural modeling shows that Glu300 lies in the ß-propeller domain, and is surrounded by several residues that are important for heterodimerization with α integrin. Previous studies showed that ITGB6 variants can cause amelogenesis imperfecta in humans, but patients from family AP91 who are homozygous for the c.898G>A variant present with neurological and dermatological features, indicating a role for ITGB6 beyond enamel formation. Our study demonstrates that a rare deleterious variant within ITGB6 causes not only dentogingival anomalies but also intellectual disability and alopecia.
Assuntos
Alopecia/genética , Cadeias beta de Integrinas/genética , Deficiência Intelectual/genética , Fenótipo , Anormalidades Dentárias/genética , Adolescente , Adulto , Alopecia/diagnóstico , Criança , Feminino , Humanos , Cadeias beta de Integrinas/química , Deficiência Intelectual/diagnóstico , Masculino , Mutação de Sentido Incorreto , Linhagem , Domínios Proteicos , Síndrome , Anormalidades Dentárias/diagnósticoRESUMO
BACKGROUND: Atrichia with papular lesions (APL) is a rare irreversible form of complete hair loss inherited in autosomal recessive manner. Hair loss is often followed by the appearance of multiple keratin-filled cysts or papules on exterior parts of the body. This phenotype results due to mutations in the human hairless gene (HR) mapped on chromosome 8p21.3. The present study was aimed to search for disease-causing sequence variants in the HR gene in five consanguineous families exhibiting features of APL. METHODS: Linkage in five Pakistani lineal consanguineous families, displaying features of APL, was tested using microsatellite markers flanking the HR gene on chromosome 8p21.3. After constructing the haplotypes, variants in the gene HR were searched by dideoxy-chain termination sequencing. RESULTS: Haplotype analysis established linkage in all five families to the HR gene located on chromosome 8p.21.3. Subsequently, sequencing HR identified a novel homozygous nonsense variant (c.2541G>A, p.Trp847*) in one and previously reported two pathogenic variants (p.Cys690*, p.Pro1157Arg) in the other four families. CONCLUSION: Mutations identified extend the spectrum of mutations in the HR gene resulting in APL. Characterizing the clinical spectrum resulting from the disease-causing homozygous variants in the HR gene will direct clinical care of the family members.