Clinical and mutational spectrum of 4 Chinese families with glutaric aciduria type 1

Abstract

Background To investigate clinical presentation and molecular aspects of five patients suffered from glutaric aciduria type I (GA-I ), a rare neurometabolic disorder caused by glutaryl-CoA dehydrogenase deficiency due to GCDH gene mutations. Methods All five patients were diagnosed by elevated urinary glutaric acid and GCDH gene analysis. Low protein diet supplemented with special formula, GABA analog and L-carnitine were initialed following laboratory confirmation of diagnosis. The clinical and biochemical features were analyzed, and mutational analysis of GCDH was conducted using Sanger sequencing. Results Clinical manifestations of 5 patients varied from macrocephaly to severe encephalopathy, with notably different phenotype between siblings with the same mutations. Three members present complex heterozygous mutations, while two sisters present homozygous mutations. Among them, four mutations in GCDH were identified (c.1133C>T 、c.1244-2A>C 、c.339delT 、c.406G>T). Of these four mutations, c.1244- 2A>C was found in four patients and c.339delT and c.1133C>T has not yet been reported until now. Conclusions In 5 Chinese patients with GA1, two novel mutations of GCDH gene were identified, which may expand the mutation spectrum of GCDH gene. What we found confirm that there is no correlation between clinical phenotype and genotype in GA-I patients, and c.1244-2A>C may be mutation hotspot in Southern China.