The incidence of MoCD is likely underestimated due to misdiagnosis of hypoxic ischemic encephalopathy (HIE) or cerebral palsy and the high early fatality rate among the severe phenotype [11–13]. MoCD diagnostic criteria include elevated urine sulfite, S-sulfocysteine, taurine, thiosulfate, xanthine and hypoxanthine, and decreased urine and serum levels of uric acid due to loss of xanthine dehydrogenase function [8]. This evidence concerns the gene XDH and perinatal asphyxia.