A mutation of aspartoacylase gene in a Turkish patient with Canavan disease: Canavan disease (CD) is an autosomal recessive inherited disorder characterized by spongy degeneration of the brain. The deficiency of aspartoacylase (ASPA), resulting in the accumulation of N-acetyl aspartic acid (NAA) in the brain, plays an important role in the pathogenesis of the disease. The cardinal features of this neurodegenerative disease are macrocephaly, mental retardation, and hypotonia. Magnetic resonance imaging (MRI) of the brain generally shows diffuse white matter degeneration and also elevated excretion of urinary NAA is usually seen. A large number of mutations were identified to date. We report here a 9 months old girl with Canavan Disease and a homozygous c.79G>A mutation in the ASPA gene, detected for the first time in Turkish population.