The first case of 4-hydroxybutyric aciduria in Japan

We report a boy with 4-hydroxybutyric aciduria resulting from a deficiency of succinic semialdehyde dehydrogenase (SSADM). A boy, 1 year 5 months, sho wed delayed walk with hypotonia and could not speak meaningful words. The b lood levels of lactate, pyruvate and amino acids were not elevated. Head ma gnetic resonance imaging (MRI) and electroenchephalography (EEG) were norma l. Urinary organic acid analysis with gas chromatography-mass spectrometry (GCMS) revealed increased levels of 4-hydroxybutyric acid, glutaric acid, a dipic acid and suberic acid. The concentrations of 4-hydroxybutyric acid an d gamma -aminobutyric acid (GABA) were elevated in the serum and cerebrospi nal fluid (CSF). SSADH activity in cultured lymphoblasts was 4.5% of the no rmal level. So far as we know this is the first Japanese patient diagnosed as 4-hydroxybutyric acid. Urinary organic acid analysis is necessary for th e diagnosis of patients with unexplained psychomotor retardation. (C) 2001 Elsevier Science B.V. All rights reserved.