The 7 genetic/metabolic disorder cases all had preceding respiratory infections within 1 week and included late-onset methylmalonic acidemia (3 cases), biotinidase deficiency (1 case), Leigh syndrome (1 case), hereditary cerebellar ataxia with ATP1A3 mutation (1 case), and adrenoleukodystrophy (1 case). This evidence concerns the gene ATP1A3 and methylmalonic acidemia.