Neonatal screening and gene mutations of children with primary carnitine deficiency in Beijing

GONG Li-fei; ZHAO Jin-qi; LIU Wei; WAN Zhi-hui; TANG Yue; LI Lu-lu; WANG Shu-nan; YANG Hai-he; KONG Yuan-yuan

doi:10.19538/j.ek2025030610

Abstract：Objective To investigate the prevalence,clinical and gene mutation characteristics of primary carnitine deficiency(PCD)in Beijing,in order to provide basis for disease diagnosis,treatment and genetic counseling.Methods The free carnitine and acylcarnitine levels in the blood of 243,898 neonates in Beijing from January 2017 to July 2023 were measured by tandem mass spectrometry(MS/MS).The clinical,biochemical and gene mutation characteristics of patients with PCD were analyzed.The symptomatic treatment was given and the growth and development were followed up.Results Among 243,898 live births,1561 had decreased free carnitine(C0)concentration in initial screeing and 1345 were recalled.Ten cases of PCD were diagnosed and the incidence of PCD was 4.1/100,000(1/24,390).Six cases of maternal PCD were confirmed.No abnormal clinical manifestations were found in all 10 patients.There was decrease in both blood C0 and multiple acylcarnitine levels.Eight mutations were detected in the SLC22A5 gene of nine patients,including 7 types of reported mutations and 1 novel mutation,with c.1400C＞G(p.S467C)as the hot spot mutation,of which three patients showed homozygous mutation,all being c.1400C＞G(p.S467C),and the rest were compound heterozygous mutations.The median follow-up age of 9 patients was 8(5,20)months,and no clinical symptoms were observed.Their growth and development were normal.Conclusion The prevalence of PCD in Beijing is 1/24,390.c.1400C＞G(p.S467C)is the hot spot mutation in PCD patients in Beijing.Patients with PCD confirmed through neonatal screening have no obvious clinical symptoms,but it is necessary to have long-term standardized treatment and follow-up.