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1.
Gene ; 696: 21-27, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30771478

RESUMO

Intellectual disabilities (ID) are etiologically heterogeneous. Advanced molecular techniques could be helpful in identification of the underlying genetic defects. We aimed to characterize clinical and molecular features of three Thai patients with ID. Patient 1 had ID, hypotonia and lactic acidosis. Patient 2 had ID and growth failure. Patient 3 had ID, seizure, diarrhea and hypoglycemia. Whole exome sequencing found that Patient 1 was homozygous for a nonsense, c.1303C>T (p.Arg435Ter), mutation in FBXL4, a gene responsible for encephalomyopathic mitochondrial DNA depletion syndrome-13 (MTDPS13). Patient 2 was compound heterozygous for two novel mutations, c.3226C>T (p.Arg1076Ter) and c.3205C>T (p.Arg1069Ter), in UNC80, a known gene of infantile hypotonia with psychomotor retardation and characteristic facies-2 (IHPRF2). Patient 3 was homozygous for a novel missense, c.427T>C (p.Cys143Arg), mutation in ADK, a known gene of adenosine kinase deficiency leading to hypermethioninemia. This study expands the mutational spectra of ID genes.


Assuntos
Adenosina Quinase/genética , Proteínas de Transporte/genética , Proteínas F-Box/genética , Testes Genéticos/métodos , Deficiência Intelectual/genética , Proteínas de Membrana/genética , Ubiquitina-Proteína Ligases/genética , Feminino , Homozigoto , Humanos , Lactente , Deficiência Intelectual/diagnóstico , Mutação , Índice de Gravidade de Doença , Tailândia , Sequenciamento Completo do Exoma
2.
Am J Med Genet A ; 176(8): 1706-1710, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30063094

RESUMO

Cole-Carpenter syndrome (CCS), commonly classified as a rare type of osteogenesis imperfecta, is a disorder with severe bone fragility, craniosynostosis, and distinct facial features. Recently, the heterozygous missense mutation, c.1178A>G, p.Tyr393Cys, in exon 9 of P4HB which encodes protein disulfide isomerase, has been found in three Caucasian patients with CCS. Ethnic background is known to affect clinical manifestations, especially facial features of dysmorphic syndromes. Here, we describe the first Asian CCS patient possessing the recurrent mutation in P4HB. Although she had several common features of CCS including bulging forehead, ocular proptosis, midface hypoplasia, long bone deformity, popcorn epiphyses, vertebral fractures, and scoliosis, she did not have hydrocephalus, wormian bones, and dentinogenesis imperfecta, commonly seen in Caucasian patients. Interestingly, she is the only one without macrocephaly. Radiologically, metadiaphyseal fractures of the long bones with metaphyseal sclerosis were found, substantiating that they provide a definitive radiological feature of CCS. In addition, we showed for the first time a three-dimensional facial scan of a patient with CCS. She had been given intravenous bisphosphonate since the age of 9 months and had responded well. Our study presents the clinical features of the first Asian patient, supports metaphyseal scleroses and fractures as radiological clues, strengthens early bisphosphonate administration, and confirms the etiologic role of the c.1178A>G variant in P4HB across populations.

3.
BMC Med Genet ; 19(1): 117, 2018 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-30012084

RESUMO

BACKGROUND: WNT1 mutations cause bone fragility as well as brain anomalies. There are some reported cases of WNT1 mutations with normal cognition. Genotype and phenotype correlation of WNT1 mutations has not been established. CASE PRESENTATION: Here we present two female siblings with osteogenesis imperfecta (OI) born to a consanguineous couple. Both sustained severe bone deformities. However, only the younger had severe brain anomalies resulting in an early death from pneumonia, while the older had normal intellectual development. Next generation sequencing showed a homozygous mutation, c.6delG, p.Leu3Serfs*36 in WNT1. To our knowledge, it is the most 5' truncating mutation to date. CONCLUSION: This report emphasizes the intrafamilial variability of brain anomalies found in this OI type and suggests that WNT1 may not be necessary for normal human cognitive development.

4.
Int J Biol Sci ; 14(4): 381-389, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29725259

RESUMO

Kabuki syndrome is a rare genetic disorder characterized by distinct dysmorphic facial features, intellectual disability, and multiple developmental abnormalities. Despite more than 350 documented cases, the oro-dental spectrum associated with kabuki syndrome and expression of KMT2D (histone-lysine N-methyltransferase 2D) or KDM6A (lysine-specific demethylase 6A) genes in tooth development have not been well defined. Here, we report seven unrelated Thai patients with Kabuki syndrome having congenital absence of teeth, malocclusion, high-arched palate, micrognathia, and deviated tooth shape and size. Exome sequencing successfully identified that six patients were heterozygous for mutations in KMT2D, and one in KDM6A. Six were novel mutations, of which five were in KMT2D and one in KDM6A. They were truncating mutations including four frameshift deletions and two nonsense mutations. The predicted non-functional KMT2D and KDM6A proteins are expected to cause disease by haploinsufficiency. Our study expands oro-dental, medical, and mutational spectra associated with Kabuki syndrome. We also demonstrate for the first time that KMT2D and KDM6A are expressed in the dental epithelium of human tooth germs.

5.
BMC Med Genet ; 18(1): 102, 2017 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-28915855

RESUMO

BACKGROUND: Hyperphenylalaninemia (HPA) can be classified into phenylketonuria (PKU) which is caused by mutations in the phenylalanine hydroxylase (PAH) gene, and BH4 deficiency caused by alterations in genes involved in tetrahydrobiopterin (BH4) biosynthesis pathway. Dietary restriction of phenylalanine is considered to be the main treatment of PKU to prevent irreversible intellectual disability. However, the same dietary intervention in BH4 deficiency patients is not as effective, as BH4 is also a cofactor in many neurotransmitter syntheses. METHOD: We utilized next generation sequencing (NGS) technique to investigate four unrelated Thai patients with hyperphenylalaninemia. RESULT: We successfully identified all eight mutant alleles in PKU or BH4-deficiency associated genes including three novel mutations, one in PAH and two in PTS, thus giving a definite diagnosis to these patients. Appropriate management can then be provided. CONCLUSION: This study identified three novel mutations in either the PAH or PTS gene and supported the use of NGS as an alternative molecular genetic approach for definite diagnosis of hyperphenylalaninemia, thus leading to proper management of these patients in Thailand.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Sequenciamento de Nucleotídeos em Larga Escala , Fenilalanina Hidroxilase/genética , Fenilcetonúrias/diagnóstico , Fósforo-Oxigênio Liases/genética , Alelos , Sequência de Aminoácidos , Biopterina/análogos & derivados , Biopterina/biossíntese , Exoma , Feminino , Genótipo , Humanos , Lactente , Masculino , Fenilcetonúrias/genética , Análise de Sequência de DNA , Tailândia
6.
Am J Med Genet A ; 173(10): 2747-2752, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28763161

RESUMO

Skeletal dysplasias are a complex group of more than 350 disorders with phenotypic and genotypic heterogeneity affecting bone and cartilage growth. We studied a 2-year-old girl and her 21-year-old mother with disproportionate short stature. In addition to typical features of hypochondroplasia found in both patients, the child had deformities of the extremity bones, metaphyseal flares, and bilateral transverse (Bowdler) fibular spurs with overlying skin dimples detected at birth. Intravenous pamidronate was started in the child since the age of 17 days, and then every two months. Exome sequencing revealed that the girl was heterozygous for a missense mutation (c.1651A>G, p.Ile538Val) in exon 13 of FGFR3, a known mutation for hypochondroplasia, inherited from her mother. Interestingly, the child also harbored compound heterozygous missense mutations in exon 12 of ALPL, c.1460C>T (p.Ala487Val) inherited from her mother and c.1479C>A (p.Asn493Lys) inherited from her healthy father. The former mutation was previously reported in perinatal hypophosphatasia while the latter was novel. Constantly reduced serum alkaline phosphatase levels including the one before the pamidronate administration and a substantially elevated level of plasma pyridoxal 5'-phosphate detected at age 28 months supported the diagnosis of hypophosphatasia. After a definite diagnosis was achieved, pamidronate was withdrawn at the age of 28 months. No adverse events were observed during pamidronate therapy. In conclusion, we describe a unique case with monoallelic FGFR3 and biallelic ALPL mutations leading to features of both hypochondroplasia and hypophosphatasia.


Assuntos
Fosfatase Alcalina/genética , Osso e Ossos/anormalidades , Nanismo/genética , Hipofosfatasia/genética , Deformidades Congênitas dos Membros/genética , Lordose/genética , Mutação , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/genética , Alelos , Osso e Ossos/patologia , Criança , Nanismo/complicações , Nanismo/patologia , Feminino , Humanos , Hipofosfatasia/complicações , Hipofosfatasia/patologia , Deformidades Congênitas dos Membros/complicações , Deformidades Congênitas dos Membros/patologia , Lordose/complicações , Lordose/patologia , Tailândia
7.
BMC Med Genet ; 18(1): 25, 2017 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-28257626

RESUMO

BACKGROUND: Osteogenesis imperfecta (OI) is a collagen-related bone dysplasia leading to a susceptibility to fractures. OI can be caused by mutations in several genes including BMP1. It encodes two isoforms, bone morphogenetic protein 1 (BMP1) and mammalian tolloid (mTLD); both have proteolytic activity to remove the C-propeptide from procollagen. CASE PRESENTATION: We report a Thai OI patient who had his first fracture at the age of three months. Using next generation sequencing, we successfully identified two novel compound heterozygous BMP1 mutations. One mutation, c.796_797delTT (p.Phe266Argfs*25) affects both BMP1 and mTLD isoforms, while the other, c.2108-2A > G, affects only the BMP1 isoform. Preservation of the mTLD may explain the relatively less severe clinical phenotype in this patient. Intravenous bisphosphonate was given from the age of 8 months to 5 years. He was free from fractures for 9 months before discontinuation. CONCLUSION: This case expands the mutation spectrum of BMP1, strengthens the correlation between genotype and phenotype, and supports the benefits of bisphosphonate in OI patients with BMP1 mutations.


Assuntos
Proteína Morfogenética Óssea 1/genética , Osteogênese Imperfeita/genética , Densidade Óssea , Criança , Fêmur/diagnóstico por imagem , Deleção de Genes , Genótipo , Heterozigoto , Humanos , Masculino , Osteogênese Imperfeita/diagnóstico , Isoformas de Proteínas/genética
8.
Genet Test Mol Biomarkers ; 21(1): 58-62, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27797586

RESUMO

OBJECTIVE: Mucopolysaccharidosis type VI (MPS VI; Maroteaux-Lamy syndrome), a rare autosomal recessive lysosomal storage disease, is caused by mutations in the N-acetylgalactosamine-4-sulfatase (arylsulfatase B, or ARSB) gene, resulting in a deficiency of ARSB activity. This study aimed to characterize the clinical and molecular features of four unrelated Thai patients with MPS VI. Two were products of consanguineous marriages. MATERIALS AND METHODS: The diagnosis was confirmed by biochemical and genetic tests. We performed mutation analysis by polymerase chain reaction-sequencing on the entire coding region of the ARSB gene. Array-based comparative genomic hybridization (aCGH) analysis combined with direct sequencing was also used to search for a deletion boundary. RESULTS: The causative mutations were detected in all cases. Of four different mutations identified, three have never been previously described, which included two missense mutations (p.C155Y and p.R388T) and a deletion encompassing exons 2 and 3. Both missense mutations were absent in 110 unaffected ethnic-matched control chromosomes and an in-house database of 180 Thai exomes. The p.C155Y and p.R388T mutations were located in highly conserved residues. A CGH analysis combined with direct sequencing identified the breakpoints of a large 13,788 base pair deletion. It is the largest deletion of ARSB described to date in patients with MPS VI. CONCLUSION: This study expanded the known mutational spectrum of ARSB; we identified three novel mutations; two of which are missense mutations and one that represents the largest deletion mutation identified to date in this gene.


Assuntos
Mucopolissacaridose VI/genética , N-Acetilgalactosamina-4-Sulfatase/genética , Adolescente , Criança , Pré-Escolar , Hibridização Genômica Comparativa , Análise Mutacional de DNA , Éxons , Feminino , Deleção de Genes , Humanos , Lactente , Masculino , Mucopolissacaridose VI/metabolismo , Mutação , Mutação de Sentido Incorreto , N-Acetilgalactosamina-4-Sulfatase/metabolismo , Deleção de Sequência
9.
BMC Med Genet ; 17(1): 96, 2016 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-27955642

RESUMO

BACKGROUND: Heterozygous mutations in COL2A1 create a spectrum of clinical entities called type II collagenopathies that range from in utero lethal to relatively mild conditions which become apparent only during adulthood. We aimed to characterize the clinical, radiological, and molecular features of a family with an atypical type II collagenopathy. CASE PRESENTATION: A family with three affected males in three generations was described. Prominent clinical findings included short stature with platyspondyly, flat midface and Pierre Robin sequence, severe dysplasia of the proximal femora, and severe retinopathy that could lead to blindness. By whole exome sequencing, a novel heterozygous deletion, c.4161_4165del, in COL2A1 was identified. The phenotype is atypical for those described for mutations in the C-propeptide region of COL2A1. CONCLUSIONS: We have described an atypical type II collagenopathy caused by a novel out-of-frame deletion in the C-propeptide region of COL2A1. Of all the reported truncating mutations in the C-propeptide region that result in short-stature type II collagenopathies, this mutation is the farthest from the C-terminal of COL2A1.


Assuntos
Colágeno Tipo II/genética , Osteocondrodisplasias/genética , Análise de Sequência de DNA/métodos , Deleção de Sequência , Grupo com Ancestrais do Continente Asiático/genética , Colágeno Tipo II/química , Exoma , Humanos , Lactente , Masculino , Tailândia
10.
Nat Commun ; 7: 11920, 2016 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-27380894

RESUMO

Osteogenesis imperfecta (OI) is a collagen-related bone dysplasia. We identified an X-linked recessive form of OI caused by defects in MBTPS2, which encodes site-2 metalloprotease (S2P). MBTPS2 missense mutations in two independent kindreds with moderate/severe OI cause substitutions at highly conserved S2P residues. Mutant S2P has normal stability, but impaired functioning in regulated intramembrane proteolysis (RIP) of OASIS, ATF6 and SREBP transcription factors, consistent with decreased proband secretion of type I collagen. Further, hydroxylation of the collagen lysine residue (K87) critical for crosslinking is reduced in proband bone tissue, consistent with decreased lysyl hydroxylase 1 in proband osteoblasts. Reduced collagen crosslinks presumptively undermine bone strength. Also, proband osteoblasts have broadly defective differentiation. These mutations provide evidence that RIP plays a fundamental role in normal bone development.


Assuntos
Membrana Celular/patologia , Colágeno Tipo I/genética , Metaloendopeptidases/genética , Mutação de Sentido Incorreto , Osteoblastos/metabolismo , Osteogênese Imperfeita/genética , Fator 6 Ativador da Transcrição/genética , Fator 6 Ativador da Transcrição/metabolismo , Adulto , Idoso , Diferenciação Celular , Membrana Celular/metabolismo , Colágeno Tipo I/deficiência , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Regulação da Expressão Gênica , Genes Recessivos , Humanos , Hidroxilação , Masculino , Metaloendopeptidases/metabolismo , Pessoa de Meia-Idade , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Osteoblastos/patologia , Osteogênese Imperfeita/metabolismo , Osteogênese Imperfeita/patologia , Linhagem , Pró-Colágeno-Lisina 2-Oxoglutarato 5-Dioxigenase/genética , Pró-Colágeno-Lisina 2-Oxoglutarato 5-Dioxigenase/metabolismo , Proteólise , Índice de Gravidade de Doença , Proteínas de Ligação a Elemento Regulador de Esterol/genética , Proteínas de Ligação a Elemento Regulador de Esterol/metabolismo
12.
Dermatology ; 231(1): 77-81, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26044244

RESUMO

BACKGROUND: Familial comedones without dyskeratosis are a rare autosomal dominant skin disorder, characterized by the occurrence of comedones that are distributed all over the body with specific features. We have previously reported two Thai families with familial comedones with expanded phenotypic spectrum. However, its genetic defect and pathogenesis remain unknown. OBJECTIVE: To explore the molecular defect causing familial comedones. METHODS: Whole-genome linkage analysis and whole-exome sequencing in family I were performed. RESULTS: We identified a heterozygous one-base pair insertion, c.84_85insT (p. L28FfsX93) in PEN-2, located within the linked region on chromosome 19. PCR-Sanger sequencing confirmed the identified mutation. The mutation segregated with the disease phenotype in family I and was fully penetrant. This similar mutation was also present in the unrelated affected individual from family II. Quantitative PCR revealed increased mRNA expression of PEN-2 in leukocytes of affected individuals. CONCLUSION: We for the first time identify PEN-2 as the causative gene of familial comedones.


Assuntos
Secretases da Proteína Precursora do Amiloide/genética , Mutação da Fase de Leitura , Proteínas de Membrana/genética , Anormalidades da Pele/genética , Dermatopatias Papuloescamosas/genética , Cromossomos Humanos Par 19 , Análise Mutacional de DNA , Exoma/genética , Feminino , Humanos , Masculino , Linhagem , Fenótipo
13.
Hum Genome Var ; 2: 15033, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-27081542

RESUMO

Propionic acidemia (PA) is an inborn error of metabolism, caused by mutations in either the PCCA or PCCB gene, leading to mitochondrial accumulation of propionyl-CoA and its by-products. Here we report a 6-year-old Thai boy with PA who was born to consanguineous parents. Exome sequencing identified a novel homozygous frameshift insertion (c.379_380insA; p.T127NfsX160) in the PCCB gene, expanding its mutational spectrum.

14.
J Med Genet ; 51(12): 817-23, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25332435

RESUMO

BACKGROUND: Split hand/split foot malformation (SHFM) type 1 is characterised by missing central digital rays with clefts of the hands and/or feet, which was linked to chromosome 7q21.3. While double knockout of Dlx5 and Dlx6 resulted in limb defects in mice, the majority of patients with SHFM1 had only heterozygous chromosomal abnormalities. OBJECTIVE: To investigate the clinical and molecular features of a large family with SHFM1. METHODS: Blood samples of family members were investigated by linkage analysis, array comparative genomic hybridisation, exome sequencing and PCR-Sanger sequencing. Cultures from bone specimens obtained from the proband and an unrelated unaffected individual were established and subjected to quantitative real-time PCR, reverse-transcribed PCR, Western blot and imprinting analysis. RESULTS: We report a large pedigree of SHFM1 with 10 members having a heterozygous 103 kb deletion, the smallest one ever reported to be associated with SHFM1. Of these 10, two had no limb anomalies, making a penetrance of 80%. The deletion encompassed exons 15 and 17 of DYNC1I1, which are known enhancers of two downstream genes, DLX5 and DLX6. Surprisingly, DLX5 and DLX6 RNA and proteins in our proband's cultured osteoblasts, instead of 50% decrease, were absent. Allelic expression studies in cultured osteoblasts of the unaffected individual showed that DSS1, DLX6 and DLX5 expressed only paternal alleles. These lines of evidence indicate that DSS1, DLX6 and DLX5 were maternally imprinted in osteoblasts. CONCLUSIONS: SHFM1 in our family is caused by a heterozygous paternal deletion of enhancers of the osteoblast-specific maternally imprinted DLX6 and DLX5 genes, leading to the absence of their proteins.


Assuntos
Impressão Genômica , Proteínas de Homeodomínio/genética , Deformidades Congênitas dos Membros/metabolismo , Fatores de Transcrição/genética , Pontos de Quebra do Cromossomo , Hibridização Genômica Comparativa , Variações do Número de Cópias de DNA , Feminino , Deformidades Congênitas do Pé/diagnóstico por imagem , Deformidades Congênitas do Pé/patologia , Expressão Gênica , Ligação Genética , Deformidades Congênitas da Mão/diagnóstico por imagem , Deformidades Congênitas da Mão/patologia , Heterozigoto , Humanos , Deformidades Congênitas dos Membros/diagnóstico , Masculino , Especificidade de Órgãos/genética , Osteoblastos/metabolismo , Linhagem , Fenótipo , Mutação Puntual , Radiografia , Deleção de Sequência
15.
J Hum Genet ; 59(8): 467-70, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24965254

RESUMO

Werner mesomelic syndrome (WMS), an autosomal dominant disorder characterized by hypoplastic tibiae, triphalangeal thumbs and polydactyly, is caused by a specific point mutation at the position 404 in zone of polarizing activity regulatory sequence (ZRS). Here we identified two additional families with WMS. All three patients in three generations of Family 1 were found to harbor the same heterozygous 406A>G mutation in ZRS. The fourth patient from Family 2 was a sporadic case with the known 404 point mutation. The novel 406A>G mutation expands mutational spectrum in ZRS causing WMS, provides evidence for a functionally important nucleotide position 406 of ZRS in humans and has implications for genetic counseling.


Assuntos
Deformidades Congênitas da Mão/genética , Mutação Puntual , Polidactilia/genética , Polegar/anormalidades , Tíbia/anormalidades , Adulto , Pré-Escolar , Elementos Facilitadores Genéticos/genética , Feminino , Predisposição Genética para Doença , Heterozigoto , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Complexos Multiproteicos , Linhagem , Fenótipo
16.
PLoS One ; 9(6): e100191, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24950249

RESUMO

Congenital heart defects (CHD) occur in 40% of patients with trisomy 21, while the other 60% have a structurally normal heart. This suggests that the increased dosage of genes on chromosome 21 is a risk factor for abnormal heart development. Interaction of genes on chromosome 21 or their gene products with certain alleles of genes on other chromosomes could contribute to CHD. Here, we identified a pair of monozygotic twins with trisomy 21 but discordant for a ventricular septal defect and epilepsy. Twin-zygosity was confirmed by microsatellite genotyping. We hypothesized that some genetic differences from post-twinning mutations caused the discordant phenotypes. Thus, next generation sequencing (NGS) technologies were applied to sequence both whole genome and exome of their leukocytes. The post-analyses of the sequencing data revealed 21 putative discordant exonic variants between the twins from either genome or exome data. However, of the 15 variants chosen for validation with conventional Sanger sequencing, these candidate variants showed no differences in both twins. The fact that no discordant DNA variants were found suggests that sequence differences of DNA from leukocytes of monozygotic twins might be extremely rare. It also emphasizes the limitation of the current NGS technology in identifying causative genes for discordant phenotypes in monozygotic twins.


Assuntos
Síndrome de Down/complicações , Síndrome de Down/genética , Epilepsia/complicações , Exoma/genética , Genômica , Comunicação Interventricular/complicações , Análise de Sequência de DNA , Sequência de Bases , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Mutação INDEL , Lactente , Recém-Nascido , Masculino , Fenótipo , Polimorfismo de Nucleotídeo Único
17.
J Clin Endocrinol Metab ; 99(8): E1487-92, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24823459

RESUMO

CONTEXT: Pituitary blastoma causing Cushing's syndrome in infancy is very rare, and its molecular pathomechanism is not well understood. OBJECTIVE: Our objective was to identify genetic changes of a pituitary blastoma causing infantile-onset Cushing's syndrome in a Thai girl without a family history of cancers. METHODS: Genomic DNA from both leukocytes and tumor tissues was used for whole-exome sequencing (WES) and Sanger sequencing of DICER1. The cDNA reverse-transcribed from RNA extracted from both leukocytes and tumor tissues was used for Sanger sequencing, quantitative real-time PCR (qRT-PCR), and pyrosequencing of DICER1. RESULTS: WES of leukocytes identified a novel heterozygous c.3046delA (p.S1016VfsX1065) mutation in the DICER1 gene. WES of the tumor tissues detected the same frameshift germline mutation and another novel somatic missense c.5438A→T (p.E1813V) mutation. Both mutations were validated by Sanger sequencing. Quantitative real-time PCR revealed that the DICER1 mRNA levels of the tumor tissues were 54% compared with those of her leukocytes. Pyrosequencing showed that the deletion allele constituted 12% and 0% of the DICER1 cDNA of the proband's leukocytes and tumor tissues, respectively. CONCLUSION: Our study extends the phenotypic and mutational spectrum of DICER1 mutations to include infantile-onset Cushing's disease and 2 novel mutations. Loss of function of both DICER1 alleles appears to be crucial to initiate tumor development.


Assuntos
RNA Helicases DEAD-box/genética , Mutação em Linhagem Germinativa , Mutação de Sentido Incorreto , Neoplasias Embrionárias de Células Germinativas/genética , Hipersecreção Hipofisária de ACTH/genética , Neoplasias Hipofisárias/genética , Ribonuclease III/genética , Fatores Etários , Feminino , Humanos , Lactente , Neoplasias Embrionárias de Células Germinativas/complicações , Neoplasias Hipofisárias/complicações , Tailândia
18.
Genet Res (Camb) ; 95(5): 133-7, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24252547

RESUMO

Summary Non-syndromic oral clefts comprising cleft lip with and without cleft palate (CL/P) and cleft palate only (CPO) are common birth defects worldwide. Their aetiology involves both environmental and genetic factors. FOXE1 has previously been reported to be associated with oral clefts in some populations. Here, we investigate whether mutations in FOXE1 play a part in the formation of oral cleft in a Thai population. We first performed PCR-RFLP to genotype a previously reported associated polymorphism, c.-1204C > G (rs111846096), in our cohort. No association was found. In addition, two unrelated unaffected controls were found to be homozygous GG, indicating that homozygous GG at this c.-1204 position was not sufficient for the development of oral clefts. We then sequenced the entire coding region of FOXE1 in 458 unrelated individuals (146 CPOs, 108 CL/Ps and 204 Thai controls). Five different non-synonymous variants, c.274G > T (p.D92Y), c.569C > G (p.P190R), c.569C > T (p.P190L), c.664C > T (p.R222C) and c.1090G > A (p.G364S), were identified in CPOs and one, c.572C > G (p.P191R), in CL/P. All these six variants were in heterozygous state, each identified in one patient, and absent in 204 controls. Except the p.P190R, which was previously reported, the other five variants were novel. Our study identifies probable susceptibility variants of FOXE1 for oral clefts in the Thai population.


Assuntos
Fenda Labial/genética , Fissura Palatina/genética , Fatores de Transcrição Forkhead/genética , Predisposição Genética para Doença , Mutação , Sequência de Bases , Primers do DNA , Humanos , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Tailândia
19.
Hum Genet ; 132(12): 1383-93, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23925499

RESUMO

Two syndromic cognitive impairment disorders have very similar craniofacial dysmorphisms. One is caused by mutations of SATB2, a transcription regulator and the other by heterozygous mutations leading to premature stop codons in UPF3B, encoding a member of the nonsense-mediated mRNA decay complex. Here we demonstrate that the products of these two causative genes function in the same pathway. We show that the SATB2 nonsense mutation in our patient leads to a truncated protein that localizes to the nucleus, forms a dimer with wild-type SATB2 and interferes with its normal activity. This suggests that the SATB2 nonsense mutation has a dominant negative effect. The patient's leukocytes had significantly decreased UPF3B mRNA compared to controls. This effect was replicated both in vitro, where siRNA knockdown of SATB2 in HEK293 cells resulted in decreased UPF3B expression, and in vivo, where embryonic tissue of Satb2 knockout mice showed significantly decreased Upf3b expression. Furthermore, chromatin immunoprecipitation demonstrates that SATB2 binds to the UPF3B promoter, and a luciferase reporter assay confirmed that SATB2 expression significantly activates gene transcription using the UPF3B promoter. These findings indicate that SATB2 activates UPF3B expression through binding to its promoter. This study emphasizes the value of recognizing disorders with similar clinical phenotypes to explore underlying mechanisms of genetic interaction.


Assuntos
Transtornos Cognitivos/genética , Anormalidades Craniofaciais/genética , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Proteínas de Ligação a RNA/genética , Fatores de Transcrição/metabolismo , Ativação Transcricional , Animais , Células COS , Células Cultivadas , Cercopithecus aethiops , Células HEK293 , Humanos , Proteínas de Ligação à Região de Interação com a Matriz/genética , Camundongos , Camundongos Knockout , Fenótipo , Regiões Promotoras Genéticas , Síndrome , Fatores de Transcrição/genética
20.
J Hum Genet ; 58(9): 594-9, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23719189

RESUMO

Gaucher disease (GD) is an autosomal recessive disorder caused by mutations in the glucocerebrosidase (GBA) gene, leading to a deficiency of lysosomal ß-glucosidase and accumulation of glycosphingolipids in macrophages. We studied five Thai families with GD (four with GD type 1 and one with GD type 2). Using long-template PCR, PCR using specific primers for the functional gene, direct sequencing of all coding regions of GBA and restriction enzyme digestions, all 10 mutant alleles were successfully identified. The common c.1448T>C (p.L483P or L444P) mutation was identified in 60% of mutant alleles. Of the two patients homozygous for the p.L483P (L444P) mutation, one died from hepatic failure at age 16 years and the other died from sepsis at age 12 years. This p.L483P (L444P) mutation was found in four different haplotypes, suggesting that it was a recurrent mutation, not caused by a founder effect. Two novel mutations, a missense (c.1204T>C, p.Y402H), and a termination codon mutation (c.1609T>C, p.X537A) were found. Studies to determine the molecular pathomechanism of the p.X537A mutation, the first of its kind in this gene, showed that it decreased the amount of protein being expressed and the enzymatic activity, while it was still correctly localized.


Assuntos
Doença de Gaucher/genética , Glucosilceramidase/genética , Grupo com Ancestrais do Continente Asiático , Feminino , Doença de Gaucher/enzimologia , Haplótipos , Humanos , Masculino , Mutação
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