RESUMO
In this interview, Kurt and Rochelle Hirschhorn talk with their son, Joel, about their research and collaborations, the early years of medical genetics, the development of genetic counseling, the challenges of being a woman in science, and new challenges and directions for the study of human genetics.
Assuntos
Genética Médica/história , Adenosina Desaminase/deficiência , Doença de Depósito de Glicogênio Tipo II , História do Século XX , História do Século XXI , Humanos , Doenças por Armazenamento dos Lisossomos , Estados Unidos , Síndrome de Wolf-HirschhornAssuntos
Consentimento Livre e Esclarecido , Sujeitos da Pesquisa , Pesquisa/legislação & jurisprudência , Risco , Manejo de Espécimes/ética , Bancos de Tecidos/ética , Ética em Pesquisa , Humanos , Consentimento Livre e Esclarecido/ética , Competência Mental , Garantia da Qualidade dos Cuidados de Saúde/ética , Garantia da Qualidade dos Cuidados de Saúde/legislação & jurisprudência , Melhoria de Qualidade/ética , Melhoria de Qualidade/legislação & jurisprudência , Bancos de Tecidos/legislação & jurisprudência , Estados UnidosRESUMO
Purine nucleoside phosphorylase (PNP) deficiency results in an autosomal recessive immunodeficiency disease characterized by initial involvement of cellular immunity and neurological manifestations with subsequent abnormalities of humoral immunity. The initial presentation and clinical course has varied widely in the relatively few published cases. The molecular basis has been reported in only 10 patients, precluding evaluation of phenotype-genotype relationships. We now report clinical, immunologic, and molecular findings in a new case of relatively early onset that emphasizes hypotonia and developmental delay as early manifestations. The patient carried two novel missense mutations (Gly56A1a and Val217Ile) on the same allele in apparent homozygosity. Expression of each of the mutant enzymes in vitro demonstrated that the Gly156A1a mutation abolished enzyme activity while the Val217Ile mutation was without obvious effect and is therefore a normal variant. Such "normal" polymorphisms might be associated with a variable response to the immunosuppressive PNP inhibitors currently in clinical trials.
Assuntos
Insuficiência de Crescimento/genética , Síndromes de Imunodeficiência/genética , Mutação de Sentido Incorreto , Doenças do Sistema Nervoso/genética , Purina-Núcleosídeo Fosforilase/deficiência , Substituição de Aminoácidos , Animais , Sequência de Bases , Células COS , Chlorocebus aethiops , DNA/química , DNA/genética , Análise Mutacional de DNA , Insuficiência de Crescimento/imunologia , Evolução Fatal , Feminino , Genes Recessivos/imunologia , Humanos , Síndromes de Imunodeficiência/imunologia , Lactente , Doenças do Sistema Nervoso/imunologia , Purina-Núcleosídeo Fosforilase/genética , Purina-Núcleosídeo Fosforilase/imunologiaRESUMO
Current methods for detection of mutations by polymerase chain reaction (PCR) and sequence analysis frequently are not able to detect heterozygous large deletions. We report the successful use of a novel approach to identify such deletions, based on detection of apparent homozygosity of contiguous single-nucleotide polymorphisms (SNPs). The sequence analysis of genomic DNA PCR products containing all coding exons and flanking introns identified only a single heterozygous mutation (IVS18+2t-->a) in a patient with classic infantile-onset autosomal recessive glycogen storage disease type II (GSDII). Apparent homozygosity for multiple contiguous SNPs detected by this sequencing suggested presence of a large deletion as the second mutation; primers flanking the region of homozygous SNPs permitted identification and characterization by PCR of a large genomic deletion (8.26 kb) extending from IVS7 to IVS15. The data clearly demonstrate the utility of SNPs as markers for large deletions in autosomal recessive diseases when only a single mutation is found, thus complementing currently standard DNA PCR sequence methods for identifying the molecular basis of disease.
Assuntos
Glucana 1,4-alfa-Glucosidase/genética , Doença de Depósito de Glicogênio Tipo II/genética , Heterozigoto , Homozigoto , Polimorfismo de Nucleotídeo Único/genética , Deleção de Sequência/genética , Sequência de Aminoácidos , Sequência de Bases , El Salvador , Éxons/genética , Glucana 1,4-alfa-Glucosidase/química , Doença de Depósito de Glicogênio Tipo II/enzimologia , Humanos , Íntrons/genética , Dados de Sequência Molecular , alfa-GlucosidasesRESUMO
Glycogen storage disease type II is an autosomal recessive muscle disorder due to deficiency of lysosomal acid alpha-glucosidase and the resulting intralysosomal accumulation of glycogen. We found six novel mutations in three Spanish classic infantile onset glycogen storage disease type II patients with involvement of both cardiac and skeletal muscle; three missense mutations (G219R, E262K, M408V), a nonsense mutation (Y191X), a donor splice site mutation (IVS18 +2gt>ga) and an in frame deletion of an asparagine residue (nt1408-1410). The missense mutations were not found in 100 normal chromosomes and therefore are not normal polymorphic variants. The splice site mutation was subsequently detected in an additional 'Spanish' infantile onset glycogen storage disease type II patient from El Salvador. Further studies will be required to determine if the IVS18 +2gt>ga splice site mutation might in fact be a relatively common Spanish mutation. Mutations among Spanish glycogen storage disease type II patients appear to be genetically heterogeneous and differ from common mutations in neighboring countries.