NEUROLOGICAL FINDINGS IN AMINOACYLASE 1 DEFICIENCY

Recessive ACY1 mutations are responsible for a novel inborn error of metabolism.1 Consistent with ACY1 deficiency (MIM 609924), all affected individuals exhibited markedly increased urinary excretion of several N -acetylated amino acids. Aminoacylase 1 (ACY1) catalyzes the release of free amino acids from a variety of N -acylated precursors, but not from N -acetylaspartate.2 The latter is hydrolyzed by aminoacylase 2 (ACY2, aspartoacylase),2 a deficiency of which is the cause of the neurodegenerative Canavan disease (MIM 271900). ### Patients. Here, we report three additional unrelated children with ACY1 deficiency detected by routine urine screening for organic acidurias by gas chromatography–mass spectrometry.1,3 One individual (OS-138II-1) is the only child of Asian consanguineous parents. She presented with febrile seizures at 11 months of age followed by further seizure episodes 3 months later associated with a viral infection. At the age of 4 years, she displays delayed speech and language development. Another patient (OS-146II-1) is the second son of healthy Romani cousins. Two cousins and a niece of the …