Clinically Distinct Phenotypes of Canavan Disease Correlate with Residual Aspartoacylase Enzyme Activity
نویسندگان
چکیده
We describe 14 patients with 12 novel missense mutations in ASPA, the gene causing Canavan disease (CD). We developed a method to study the effect of these 12 variants on the function of aspartoacylase-the hydrolysis of N-acetyl-l-aspartic acid (NAA) to aspartate and acetate. The wild-type ASPA open reading frame (ORF) and the ORFs containing each of the variants were transfected into HEK293 cells. Enzyme activity was determined by incubating cell lysates with NAA and measuring the released aspartic acid by LC-MS/MS. Clinical data were obtained for 11 patients by means of questionnaires. Four patients presented with a non-typical clinical picture or with the milder form of CD, whereas seven presented with severe CD. The mutations found in the mild patients corresponded to the variants with the highest residual enzyme activities, suggesting that this assay can help evaluate unknown variants found in patients with atypical presentation. We have detected a correlation between clinical presentation, enzyme activity, and genotype for CD.
منابع مشابه
Canavan disease: studies on the knockout mouse.
Canavan disease (CD) is an autosomal recessive disorder, characterized by spongy degeneration of the brain. Patients with CD have aspartoacylase (ASPA) deficiency, which results accumulation of N-acetylaspartic acid (NAA) in the brain and elevated excretion of urinary NAA. Clinically, patients with CD have macrocephaly, mental retardation and hypotonia. A knockout mouse for CD which was enginee...
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متن کاملTwo novel aspartoacylase gene (ASPA) missense mutations specific to Norwegian and Swedish patients with Canavan disease.
Canavan disease (CD) (OMIM 271900) is an autosomal recessive leucodystrophy characterised by swelling and spongy degeneration of the white matter of the brain. The biochemical marker for the disorder is increased level of N-acetylaspartic acid (NAA) in cerebrospinal fluid and urine owing to aspartoacylase (ASPA) deficiency. 2 The disease is caused by mutations in the gene encoding the enzyme as...
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