[Studies on the clinical manifestation and SLC25A13 gene mutation of Chinese patients with neonatal intrahepatic cholestasis caused by citrin deficiency].

OBJECTIVE: To investigate the clinical and laboratory features of neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and to characterize the molecular basis and prognosis of this disease.

METHODS: Twenty-six patients with NICCD were collected because of idiopathic intrahepatic cholestasis and jaundice. The diagnosis was made by routine laboratory data collection, tandem mass spectrometry (MS-MS) and gas chromatography mass spectrometry (GC-MS) analyses. SLC25A13 gene mutation was analyzed by using polymerase chain reaction (PCR), direct DNA sequencing and restriction fragment length polymorphism analyses. The patients were followed up for nearly 2 years.

RESULTS: The NICCD patients showed low birth weight and the average onset of jaundice was 29 days. Laboratory data showed liver dysfunction, hyperbilirubinemia, hypoproteinemia, high levels of alpha-fetoprotein, prolonged prothrombin time, hypoglycemia and hyperammonemia. MS-MS analysis of the blood samples revealed specific elevation of citrulline, methionine, threonine, tyrosine and elevation of free carnitine, short-chain and long-chain acylcarnitines. GC-MS analysis of the urine samples showed elevated 4-hydroxyl phenyllactic acid and 4-hydroxyl phenylpyruvic acid. Twelve different mutations were identified, including 4 novel mutations, i.e., G386V, R467X, K453R and 1192-1193delT. Forty-four mutated alleles were identified in the 52 alleles (84.6% ). Among them, 851del4, 1638ins23 and IVS6+5G>A mutations were the most frequent mutations, accounting for 40.9%, 20.5% and 11.4% of the total alleles examined respectively. Five of the 26 patients have not been recovered, including 4 died and 1 accepted liver transplantation. No obvious relationship was found between the genotype and phenotype in NICCD.

CONCLUSION: The 851del4, 1638ins23 and IVS6+5G>A mutations are the hot-spot mutations in Chinese NICCD patients. Some NICCD patients have poor prognosis.