Macrocephaly as a feature of inborn errors of metabolism

Background. Macrocephaly may be a leading sign of neurometabolic diseases a nd thus a guide for metabolic work-up. Illustrated by reports of four patie nts the group of neurometabolic diseases presenting with macrocephaly is di scussed. Patients. We present case histories on the clinical course, biochemical and radiologic findings of patients with glutaric aciduria type I, Canavan's D isease, L-2-OH-glutaric aciduria and one patient with macrocephaly and isol ated complex I deficiency of the respiratory chain. Discussion. According to the relative frequency of organoacidurias and the option of preventive treatment for patients with glutaric aciduria type I, organic acid analysis should be performed vigorously also in neurologically asymptomatic patients with unclear macrocephaly. MR Spectroscopy might be diagnostically helpful in patients with Canavan's Disease or can provide in formation on intracerebral metabolites in diseases of unknown etiology (e.g . L-2-Hydroxyglutaric aciduria). Macrocephaly in a patient with isolated co mplex I deficiency of the respiratory chain illustrates, that it may be a f acultative finding in other neurometabolic diseases commonly not associated with macrocephaly.