RESUMO
PURPOSE: To report a novel mutation in the GUCY2D gene in a Japanese family with autosomal dominant cone-rod dystrophy (adCORD), and to examine the possible use of arrayed primer extension (APEX)-based genotyping chip in detecting mutations. METHODS: Genomic DNA was extracted from the peripheral blood of family members with adCORD. It was PCR-amplified, fragmented, and hybridized to APEX-based genotyping microarrays on which known disease-associated sequence variations were arrayed for patients with early-onset retinal dystrophy. All coding exons of the GUCY2D gene were directly sequenced. The PCR amplicon carrying a novel mutation was subcloned, and each clone was sequenced. RESULTS: Five single nucleotide polymorphisms in AIPL1, RPGRIP1, and GUCY2D were detected in the proband by microarray screening, and all were validated by direct sequencing. A novel heterozygous triple missense mutation of c.2540_2542delinsTCC (p.Gln847_Lys848delinsLeuGln amino acid substitutions) was found in both the proband and his father, and the three nucleotide changes were located on the same chromosome. Electroretinography (ERGs) demonstrated a significant reduction in rod function and a complete absence of cone function in both affected individuals. CONCLUSIONS: A novel heterozygous triple consecutive missense mutation in the GUCY2D gene has been linked to adCORD. Our study demonstrates that the APEX-based gene screening can be used to identify simultaneously disease-modifying sequence changes as well as disease-causing mutations, once proper and comprehensive sites of sequence variations of the disease are arrayed.
Assuntos
Povo Asiático/genética , Guanilato Ciclase/genética , Mutação de Sentido Incorreto , Receptores de Superfície Celular/genética , Retinose Pigmentar/genética , Idoso , Eletrorretinografia , Angiofluoresceinografia , Fundo de Olho , Genótipo , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Sequência com Séries de Oligonucleotídeos , Linhagem , Polimorfismo de Nucleotídeo Único , Retinose Pigmentar/diagnóstico , Retinose Pigmentar/fisiopatologiaRESUMO
CASE REPORT: To report the case of a 26-year-old woman with a family history of dominant optic atrophy who requested DNA testing and counselling. Ophthalmologic examination showed her affected father had bilateral temporal papillary pallor. Direct genomic sequencing of the OPA1 gene revealed a novel heterozygous nonsense mutation (Arg879stop). Because no mutation in OPA1 was detected in the daughter, we could counsel her that the possibility was very low that she was a carrier or would pass the disease-causing gene to her children. COMMENTS: Our study provides evidence of the apparent value of molecular genetic analysis of OPA1 gene as predictive DNA testing, although the exact risk and benefit of this type of analysis awaits further study.
Assuntos
Códon sem Sentido , GTP Fosfo-Hidrolases/genética , Atrofia Óptica Autossômica Dominante/genética , Adulto , Análise Mutacional de DNA , Feminino , Genes Dominantes , Aconselhamento Genético , Humanos , Masculino , Pessoa de Meia-Idade , Linhagem , PrognósticoAssuntos
Oftalmopatias Hereditárias/diagnóstico , Oftalmopatias Hereditárias/genética , Testes Genéticos , Técnicas de Diagnóstico Molecular , Distrofias Hereditárias da Córnea/diagnóstico , Distrofias Hereditárias da Córnea/genética , Diagnóstico Diferencial , Humanos , Fator de Crescimento Transformador beta/genéticaRESUMO
PURPOSE: Proliferative diabetic retinopathy (PDR) results from the formation of fibrovascular membranes (FVMs) in the posterior fundus that can lead to a severe decrease of vision. Tumor endothelial marker 7 (TEM7) is a protein that is highly expressed in the endothelial cells of tumors, but whether it plays a role in FVMs is unknown. The purpose of this study was to determine whether TEM7 is associated with the formation of FVMs. METHODS: FVMs were obtained during vitrectomy from patients with PDR. RT-PCR was performed to determine the level of expression of the mRNA of TEM7. The splice variants of TEM7 were identified by direct sequencing. Immunohistochemical analyses and in situ hybridization was performed to determine the sites of TEM7 in the FVMs. RESULTS: The level of the mRNA of TEM7 was high in 10 of 10 FVMs but was barely detectable in the five idiopathic epiretinal membranes. Direct sequencing of subcloned TEM7 PCR products revealed several splice variants (intracellular, secreted, and membrane-bound forms of TEM7) in the FVMs. Immunohistochemical analysis showed a colocalization of TEM7 and CD34, an endothelial cell marker, in most of the neovascular endothelial cells in the FVMs. Immunoelectron microscopy revealed that membrane-bound TEM7 was expressed on the luminal surfaces of the vascular endothelial cells of FVMs. CONCLUSIONS: This study indicates that TEM7 may play a significant role in the proliferation and maintenance of neovascular endothelial cells in the FVMs. If correct, TEM7 may be a molecular target for new diagnostic and therapeutic strategies for PDR.