Abstract Objective To study the gene mutation profile of primary carnitine deficiency (PCD) in neonates, and to provide a theoretical basis for early diagnosis and treatment, genetic counseling, and prenatal diagnosis of PCD. Methods Acylcarnitine profile analysis was performed by tandem mass spectrometry using 34 167 dry blood spots on filter paper. The SLC22A5 gene was sequenced and analyzed in neonates with free carnitine (C0) levels lower than 10 μmol/L as well as their parents. Results In the acylcarnitine profile analysis, a C0 level lower than 10 μmol/L was found in 10 neonates, but C0 level was not reduced in their mothers. The 10 neonates had 10 types of mutations at 20 different sites in the SLC22A5 gene, which included 4 previously unreported mutations:c.976C > T, c.919delG, c.517delC, and c.338G > A. Bioinformatics analysis showed that the four new mutations were associated with a risk of high pathogenicity. Conclusions Tandem mass spectrometry combined with SLC22A5 gene sequencing may be useful for the early diagnosis of PCD. Identification of new mutations enriches the SLC22A5 gene mutation profile.
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