RESUMO
We report a unique mutation in the D-amino acid oxidase gene (R199W DAO) associated with classical adult onset familial amyotrophic lateral sclerosis (FALS) in a three generational FALS kindred, after candidate gene screening in a 14.52 cM region on chromosome 12q22-23 linked to disease. Neuronal cell lines expressing R199W DAO showed decreased viability and increased ubiquitinated aggregates compared with cells expressing the wild-type protein. Similarly, lentiviral-mediated expression of R199W DAO in primary motor neuron cultures caused increased TUNEL labeling. This effect was also observed when motor neurons were cocultured on transduced astrocytes expressing R199W, indicating that the motor neuron cell death induced by this mutation is mediated by both cell autonomous and noncell autonomous processes. DAO controls the level of D-serine, which accumulates in the spinal cord in cases of sporadic ALS and in a mouse model of ALS, indicating that this abnormality may represent a fundamental component of ALS pathogenesis.
Assuntos
Esclerose Lateral Amiotrófica/enzimologia , Esclerose Lateral Amiotrófica/genética , D-Aminoácido Oxidase/genética , D-Aminoácido Oxidase/fisiologia , Mutação , Animais , Apoptose , Células COS , Linhagem Celular , Chlorocebus aethiops , Feminino , Ligação Genética , Masculino , Camundongos , Repetições de Microssatélites , Neurônios Motores/metabolismo , Doenças Neurodegenerativas/genética , Neurônios/metabolismo , RatosRESUMO
Familial amyotrophic lateral sclerosis (FALS) affects 5%-10% of cases of amyotrophic lateral sclerosis (ALS) and is inherited as an autosomal dominant condition with incomplete penetrance. One-fifth of these cases of FALS are associated with mutations in copper/zinc-dependent superoxide dismutase (SOD1), but the gene defect in the remaining 80% of familial cases is, as yet, unknown. We have carried out a preliminary genome screen, using a U.K. resource of families lacking SOD1 mutations, to identify other potential disease loci and have identified a putative locus on chromosome 16q12.1-q12.2. The region associated with disease was further refined in the major family that contributed to this result and was localized to D16S409-D16S3032, a 14.74-cM genetic interval that corresponds to a physical distance of 6.6 Mb, which coincides with a region independently identified by two further research groups in the United States and the United Kingdom.
