Korean Experiences of Citrin Deficiency: Seven cases of citrin deficiency and nine major mutation screening in newborns in Korea

한국인에서의 사이트린 결핍증의 경험

Citrin deficiency resulting from mutations of SLC25A13is associated with two major clinical phenotypes; neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and adult-onset type 2 citrullinemia (CTLN2). In Korea, 7 cases of citrin deficiency have been diagnosed based on biochemical and molecular findings. Four NICCD cases were identified by newborn screening using MS/MS or presenting symptoms like cholestatic jaundice. They are all males, presenting with conjugated hyperbilirubinemia, elevated liver enzymes, hypoalbuminemia, mild hyperammonemia, elevated citrullin, methionine and threonine. All of them have been spontaneously recovered from hepatic manifestation by the age of 6-8 months. Mutation analysis has been performed using their genomic & cDNAs obtained from skin fibroblasts. They turned out to be compound heterozygotes carrying each of 851del4, IVS11+1G>A, and IVS13+1G>A. Three CTLN2 patients were identified. Two adult male patients presented with a sudden loss of consciousness, seizure, vomiting, hyperammonemia and citrullinemia in their twenties. They carried an IVS13+1G>A, 851del4, and IVS11+1G>A mutant alleles. The other CTLN2 patient was 52 year old female patient, manifesting lethargy, altered consciousness, irritability and hyperammonemia. Similar clinical symptoms had recurred at the delivery of first and second babies in her past medical history. She was managed by hemodialysis and survived with neurological sequellae. Also, we screened the presence of 9 common mutations in 500 Korean newborns using dried blood spot of filter papers. Only a allele carried 854del4 mutation. In conclusion, the entire picture of citrin deficiency in Korea including incidence, genotype, clinical features and natural courses, is still vague at the present time.