Glutaric aciduria type 1: a review of phenotypic and genetic characteristics

Abstract

Glutaric aciduria type I (GA1) is an inherited metabolic disorder in which excessive levels of the amino acids lysine, hydroxylysine, and tryptophan accumulate in the body as a result of defective glutaryl-CoA dehydrogenase (GCDH) enzyme activity. Excessive metabolites are toxic that can cause damage to the brain, particularly due to the occurrence of basal ganglia and intellectual disability. Missense, splicing, and other deletion mutations in GCDH gene lead to the deficiency of the enzyme activity and are known to cause GA1. The severity of GA1 along with its neurological manifestations and clinical outcome is dependent upon the age at onset and therefore, early definitive diagnosis of GA1 becomes essential. GA1 occurs in approximately 1 of every 30,000-40,000 individuals worldwide that may reach up to 1 in 300 newborn babies in the Amish and Canadian communities. Owing to very high consanguinity rates in Saudi Arabia, it is presumed to be much more common in the Kingdom and is one of the initial disorders that were included in the country's neonatal screening program. In the current study, we have reviewed clinical manifestations, diagnosis, updated management, and mutation spectrum in GA1 with an example of one of our patients with GA1, and highlighted the importance of multipara-metric strategy in the early diagnosis and management of the disease.