RESUMEN
A 14-year girl was admitted with akinesia and difficulty walking due to gait instability after two oral doses of compound diphenoxylate (lomotil). When she was 18-month old, drowsiness and inability to walk were observed after taking lomotil, the symptoms were relieved by taking B vitamins for treatment. The laboratory tests showed the increased blood branched chain amino acid levels; gene detection indicated that the child had compound heterozygous variations of c.745G>A(p.G249S) and c.485-1G>C in the BCKDHA gene. The girl was finally diagnosed as maple syrup urine disease. The domestic and foreign literature was searched, and 11 child cases of maple syrup urine disease with onset of unsteadiness and ataxia were reported, none of whom was associated with oral administration of compound diphenoxylate.