| A rare genetic inborn error of branched-chain amino acid metabolism disorder, with a highly variable clinical and biochemical phenotype. Typical characteristics are mild to severe global developmental delay, elevated methylmalonic acid and occasionally lactic acid plasma levels and chronic methylmalonic aciduria, which may be accompanied by elevation of additional organic or amino acids in urine (for example beta-alanine, methionine, 3-hydroxypropionic, 3-aminoisobutyric and/or 3-hydroxyisobutyric acid). Microcephaly, mild craniofacial dysmorphism, axial hypotonia, liver failure and central nervous system abnormalities on MRI have also been reported. Caused by homozygous or compound heterozygous mutation in the ALDH6A1 gene on chromosome 14q24. |
