[Clinical phenotype and novel mutation in one of twins with glutaric acidemia type I].

To review the clinical features of a male twin affected with glutaric academia type I (GA-I) and analyze the variations of glutaryl-CoA dehydrogenase (GCDH) gene.Clinical data of the pair of twins and their parents were collected. Genomic DNA was extracted from peripheral blood samples, and variants of GCDH genes were detected by capture sequencing using a customized panel. Variants of the twins and their parents were verified by Sanger sequencing.The level of glutaric acyl carnitine (C5DC + C6OH) was 3.26 μmol/L in the male twin. The relative level of glutaric acid in urine was 547.51 by gas chromatography mass spectrometry analysis. Cerebral ultrasonography showed that the patient had subependymal hemorrhage, but no serious clinical manifestation was noted. After treating with special formula milk powder and L-carnitine, the boy showed good growth and development. Two heterozygous variants of the GCDH gene were detected in the patient, among which c.416C>G was suspected to be pathogenic, while c.109_110delCA was unreported. The variants were respectively inherited from his parents. The twin girl only carried the c.416C>G variant.GA-I can be diagnosed by mass spectrometry, urine gas chromatographic mass spectrometry, imaging as well as genetic diagnosis. Early diagnosis and intervention is important.