Clinical features. The autosomal recessive (17p13-ter) Canavan's disease (spongiform leukodystrophy) is characterized by megalencephaly, psychomotor retardation, and mental decline. A congenital form and a juvenile form with onset of ataxia and spasticity at school age have been described, in addition to the typical infantile form with onset before age 1 (Toft et al., 1993).
Diagnosis. Examination of the organic acids in the urine (morning urine sample, with a preservative when shipped) show an increase in N-acetylaspartate. The underlying defect in aspartoacylase is detectable in fibroblasts.
Clinical features. L-2-Hydroxyglutaric aciduria is characterized by subcortical white matter lesions and is associated with macrocephaly, psychomotor retardation, seizures, spasticity, dystonia, and/or ataxia. Patients identified so far have been diagnosed between ages 0 and 60 (Fujitake et al., 1999).
Diagnosis. Again, examination of the organic acids in the urine shows an increase in L-2-hydroxyglutarate.