Screening and SLC22A5 gene mutations of the patients with primary carnitine deficiency

Abstract

Objective To investigate the clinical features and SLC22A5 gene mutation types in patients with primary carnitine deficiency(PCD). Methods The free carnitine(C0) and acylcarnitine levels in the blood of 210 908 neonates from newborn screening program and 576 children with suspected clinical inherited metabolic diseases were measured by using liquid chromatography tandem mass spectrometry method during September 2015 to December 2017, after that the SLC22A5 gene mutations were analyzed in the children with low C0 level and the diagnosis was made.The clinical characteristics, laboratory findings, genotypes, treatment and prognosis were retrospectively analyzed in patients.Paired sample t test was used to compare the biochemical indexes of patients before and after the treatments. Results Ten children were diagnosed with PCD(9 cases from newborn screening program, 1 case from clinical patients), and 7 children were diagnosed with maternal carnitine deficiency.After treatment with oral Levocarnitine, the free carnitine and acylcarnitine of the patients returned to the normal levels.The clinical symptoms disappeared in 1 patient out of clinical patients, and the other 16 patients from newborn screening program were asymptomatic and showed normal growth and development.Seventeen patients got genetic analysis, and 10 types of mutations were found, including c. 1400C>G, c.1462C>T, c.797C>T, c.95A>G, c.92C>T, c.1093A>C, c.761G>A, c.865C>T, c.428C>T, c.1195C>T, among which two of them (c.1093A>C and c. 92C>T) were novel mutations.The most common mutation of SLC22A5 gene was c. 1400C>G. Conclusions Liquid chromatography tandem mass spectrometry technology is sufficient to screen newborns and maternal carnitine deficiency, and the c. 1400C>G mutation is found at the highest frequency in Xuzhou area.If patients receive early treatment, they may have a good prognosis. Key words: Primary carnitine deficiency; Tandem mass spectrometry; Free carnitine; SLC22A5 gene