Maternal Glutaric aciduria type I and newborn screening

Introduction: Expanded Newborn Screening (NBS) programs based on MS/MS, result in a massive increase of screened metabolic disorders and detected patients. Alongside with the detection of classical forms of screened metabolic disorders, milder forms (many whose existence was unknown until now) are being detected, representing major challenges in respect to follow up protocols. Disease spectrum of screened disorders is being stretched, through the detection of undiagnosed mothers through their son’s newborn screening results. In these cases, abnormal screening results are due to maternal rather to neonatal disease. The most common examples are newborns from mothers 3-mthylcroyonyl-CoA-carboxylase deficiency (with newborns usually presenting elevated 3-hydroxy-isovalerylcarnitine and/or low free carnitine) and from mothers with Primary Carnitine Deficiency (with newborns usually presenting low free carnitine). More rarely low free carnitne values in the newborns have been associated to other maternal conditions, namely glutaric aciduria type I. Glutaric aciduria type I (GAI) (MIM# 231670) is an autosomal recessive inherited metabolic caused by a defect of the enzyme glutaryl-CoA dehydrogenase. Clinically GAI, a neurometabolic disorder firstly described by Goodman is characterised by a progressive neurodegeneration that typically manifests acutely in infants during a intercorrent illness. The well known phenotypic presentations are fronto-temporal brain atrophy with macrocephaly and acute encephalopathic episodes with striatal necrosis followed by dystonic-dyskinetic movement disorder.