Variable clinical presentation in three patients with 3-methylglutaconyl-coenzyme A hydratase deficiency

3-Methylglutaconyl-coenzyme A (3-MG-CoA) hydratase deficiency (type I 3-methylglutaconic aciduria), a rare defect of L-leucine catabolism, has previously been identified in 5 patients (four families). Clinical findings in 3 were mild, with delayed speech development in 2 siblings, and bronchiolitis, mild hyperchloraemic acidosis, and gastro-oesophageal reflux in a third patient (Narisawa et al 1986; Gibson et al 1992). In two recently described patients, a more severe presentation was observed. The presentation included vomiting, seizures, coma, speech retardation, hepatomegaly, and decerebrate posture in one patient in whom the provisional diagnosis was Reye syndrome (Hou and Wang 1995). In another patient, the clinical picture encompassed psychomotor retardation, failure to thrive, spastic quadriplegia, dystonic involuntary movements in the upper limbs, and bilateral atrophic changes of the basal ganglia (Shoji et al 1996). We present 3 patients with 3-MG-CoA hydratase deficiency who also manifested widely differing clinical presentations, bringing to eight the total number of patients with documented 3-MG-CoA hydratase deficiency.