The mutation spectrum of the SLC25A13 gene in Chinese infants with intrahepatic cholestasis and aminoacidemia.

BACKGROUND

SLC25A13 gene mutations cause citrin deficiency, which leads to neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). Information on the mutation spectrum of SLC25A13 in the Chinese population is limited. The aim of this study was to explore the mutation spectrum of the SLC25A13 gene in Chinese infants with intrahepatic cholestasis and various forms of aminoacidemia.

METHODS

Sequence analyses were performed on 39 infants with intrahepatic cholestasis and various forms of aminoacidemia. Novel mutations were subjected to homology and structural analyses. Western blots were performed when liver specimens available.

RESULTS

Genetic testing revealed the presence of SLC25A13 gene mutations (9 heterozygotes, 6 homozygotes and 13 compound heterozygotes) in 28 infants. Subsequent Western blot analysis revealed 22 cases of citrin deficiency, accounting for 56.4% of the 39 patients. Twelve types of mutations, including nine known mutations and three novel mutations, were found. Of the 49 mutated alleles, known ones include 851del4 (26 alleles, 53.1%), 1638ins23 (6 alleles, 12.2%), IVSl6ins3kb (3 alleles, 6.1%), IVS6+5G>A (2 alleles, 4.1%), E601K (2 alleles, 4.1%) and IVS11+1G>A, R184X, R360X and R585H (1 allele each, 2.0%). The three novel mutations were a splice site change (IVS6+1G>A), a deletion mutation (1092_1095delT) and a missense mutation (L85P), each in one allele.

CONCLUSIONS

The mutation spectrum of the SLC25A13 gene in a Chinese population of infants with intrahepatic cholestasis with various forms of aminoacidemia was found to be different from that of other population groups in East Asia. The SLC25A13 gene mutation is the most important cause of infantile intrahepatic cholestasis with various forms of aminoacidemia.