SLC25A13 gene analysis in neonates with intrahepatic cholestasis caused by citrin deficiency

OBJECTIVE Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) which resulted from mutation in SLC25A13 gene can present transient intrahepatic cholestasis, low birth weight, growth retardation, hypoproteinemia and so on. This study aimed to identify the mutation type of NICCD patients by DNA sequencing. METHODS Twenty children diagnosed as NICCD were consented to enroll in this study. PCR assays were performed to amplify the eighteen exons and its flanking sequences of SLC25A13 gene, which were defined as the upstream and downstream 50 bp from starting and ending site of the exons. Then the PCR products were purified and followed by automated DNA sequencing. The IVS16ins3kb mutation was detected by nested PCR and RT-PCR. RESULTS Seven genetic variations of SLC25A13, termed as 851del4, 1638ins23, IVS16ins3kb, IVS6+5G>A, c.775C>T (p.Q259X), c.1505C>T (p.P502L) and c.1311C>T (p.C437C), were identified in the subjects, of which c.775C>T (p.Q259X), c.1505C>T (p.P502L) and c.1311C>T (p.C437C) were reported for the first time in NICCD patients. And a compound mutation of［1638ins23+IVS16ins3kb］was also identified. In 20 patients with NICCD, 6 patients were 851del4 homozygotes, 7 patients were compound heterozygotes, and 7 patients were heterozygotes of single mutation. 851del4 was the major mutation type (64%), followed by 1638ins23 (15%), IVS16ins3kb (12%) and IVS6+5G>A (6%). CONCLUSIONS 851del4 is the major mutation type in Chinese patients with NICCD.