[Clinical and genetic characteristics of primary carnitine deficiency identified by neonatal screening].

To study the prevalence, clinical and genetic characteristics of primary carnitine deficiency (PCD).From January 2013 to December 2017, 720 667 newborns and their mothers were tested for PCD by tandem mass spectrometry. Potential mutations of carnitine transporter gene SLC22A5 among suspected PCD patients were analyzed. Dietary guidance and L-carnitine supplementation were provided to the parents. Growth and intelligence development were surveyed during follow-up.In total 21 neonates and 6 mothers were diagnosed with PCD, which yielded an incidence of 1 in 34 317. Eighteen SLC22A5 mutations were detected, which included 4 novel mutations, namely c.1484T>C, c.394-1G>T, c.431T>C and c.265-266insGGCTCGCCACC. Eighteen patients were found to carry compound heterozygous mutations and 3 have carried homozygous SLC22A5 mutations. Three mothers carried compound heterozygous mutations and 2 carried homozygous mutations. Common mutations included c.1400C>G (42.3%), c.760C>T (11.5%) and c.51C>G (7.7%). During the 8-42 month follow-up, neonates with PCD showed no clinical symptoms but normal growth. Blood level of free carnitine was raised in all mothers after the treatment.The incidence of neonatal PCD in Henan is 1 in 34 317, with the most common mutation being c.1400C>G. Above finding has enriched the spectrum of SLC22A5 gene mutations.