Screening strategy and genetic mutation analysis of citrin deficiency among newborns in Xuzhou / 中国新生儿科杂志

ABSTRACT

Objective:To study the incidence, clinical features and genetic mutation profiles of neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) using screening strategy.Methods:From September 2015 to September 2020, neonates in Xuzhou area were prospectively screened for genetic metabolic diseases using tandem mass spectrometry. Suspected infants were further confirmed using urinary organic acid test and SLC25A13 gene mutation analysis. The clinical manifestations, biochemical and gene mutation results, treatment and prognosis of the confirmed cases were analyzed.Results:A total of 468,494 live-birth newborns were screened with 112 cases suspected and 95 cases received urinary organic acid test and SLC25A13 gene mutation analysis. 13 cases of NICCD were diagnosed with a prevalence of 1/36,038. Most confirmed cases presented with delayed disappearance of neonatal jaundice, feeding difficulties and poor weight gain. Biochemical changes included increased bile acid, abnormal liver enzymes, increased alpha-fetoprotein, hypoglycemia, decreased hemoglobin, abnormal coagulation function and increased blood ammonia. Tandem mass spectrometry showed increased citrulline, methionine, arginine, tyrosine and phenylalanine, and in some cases with slightly increased acylcarnitine. Urine organic acid analysis mainly showed increased 4-hydroxyphenyllactic acid and 4-hydroxyphenylpyruvate. All confirmed cases received genetic mutation tests and a total of 13 mutation loci were detected, including c.852_855delTATG, c.511dupG, c.1638_1660dup, IVS16ins3kb, c.1078C>T, c. 615+5G>A, c.742G>A, c.44G>A, c.1311+1G>A, c.1399C>T, c.889G>T, c.1177+1G>A, c.1841+3_1841+4del, among which, c.852_855delTATG was the most common one. A total of 5 novel mutation loci were discovered in this study with c.1841+3_1841+4del, c.511dupG and c.889G>T predicted as pathogenic variants. Special formula of lactose-free and fortified medium-chain triglyceride (MCT) were used in confirmed cases and most of the symptoms were relieved within 1 year and abnormal indicators significantly improved.Conclusions:The prevalence of NICCD in Xuzhou was 1/36,038. c.852_855delTATG mutation is the most frequent one. Five novel mutation loci are discovered, expanding the SLC25A13 gene mutation spectrum. Most infants with NICCD have a good prognosis, requiring early diagnosis, treatment and life-long follow-up.