Spastic diplegia and periventricular white matter abnormalities in 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiency, a defect of isoleucine metabolism: differential diagnosis with hypoxic-ischemic brain diseases.
A 19-month-old boy with 2-methyl-3-hydroxybutyryl-CoA dehydrogenase (MHBD) deficiency, a defect of isoleucine degradation, had cognitive and motor development delay, spastic diplegia, dysmorphism, and occipital periventricular white matter lesions on MRI scan of the brain. The urinary accumulation of the isoleucine metabolites 2-methyl-3-hydroxybutyrate and tiglylglycine was only moderate under basal conditions. These abnormalities became more pronounced after a 100mg/kg oral isoleucine challenge. Enzyme studies showed a markedly decreased activity of MHBD in fibroblasts and lymphocytes. Sequence analysis of the involved X-chromosome gene (HADH2), revealed the presence of 364C -->G mutation in the patient. His mother was heterozygous for the 364C-->G mutation, whereas the mutation was not found in the other members of the family (father, brother, and sister). This report indicates that an enzyme defect in the metabolism of branched-chain fatty acid oxidation and isoleucine may present features resembling sequelae of neonatal hypoxic-ischemic brain injury. All patients with MHBD deficiency identified so far are characterized by a neurologic phenotype rather than ketoacidotic attacks, unlike patients with the related isoleucine defect beta-ketothiolase deficiency.
Poll-The
Bwee Tien
BT
Department of Pediatrics, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. b.t.pollthe@amc.uva.nl
Wanders
Ronald J A
RJ
Ruiter
Jos P N
JP
Ofman
Rob
R
Majoie
Charles B L M
CB
Barth
Peter G
PG
Duran
Marinus
M
D015094:3-Hydroxyacyl CoA Dehydrogenases; D000015:Abnormalities, Multiple / Q000175:diagnosis* / Q000201:enzymology; D000429:Alcohol Oxidoreductases / Q000172:deficiency*; D000592:Amino Acid Metabolism, Inborn Errors / Q000175:diagnosis; D002547:Cerebral Palsy / Q000175:diagnosis*; D004252:DNA Mutational Analysis; D003937:Diagnosis, Differential; D006801:Humans; D000860:Hypoxia; D007223:Infant; D007231:Infant, Newborn; D007532:Isoleucine / Q000378:metabolism*; D007969:Leukomalacia, Periventricular / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D009154:Mutation
D007532:Isoleucine; D000429:Alcohol Oxidoreductases; D015094:3-Hydroxyacyl CoA Dehydrogenases; C419903:2-methyl-3-hydroxybutyryl-coenzyme A dehydrogenase