Neonatal intrahepatic cholestasis caused by citrin deficiency (
NICCD) is a kind of
inborn errors of metabolism, with the main clinic manifestations of
jaundice,
hepatomegaly, and abnormal liver function indices. As a mitochondrial
solute carrier protein,
citrin plays important roles in aerobic glycolysis, gluconeogenesis,
urea cycle, and
protein and
nucleotide syntheses. Therefore
citrin deficiency causes various and complicated metabolic disturbances, such as
hypoglycemia, hyperlactic acidemia,
hyperammonemia,
hypoproteinemia,
hyperlipidemia, and
galactosemia. This paper reported a case of
NICCD confirmed by mutation analysis of SLC25A13, the gene encoding
citrin. The baby (male, 6 months old) was referred to the First Affiliated Hospital with the complaint of
jaundice of the skin and sclera, which it had suffered from for nearly 6 months. Physical examination showed obvious
jaundice and a palpable liver 5 cm below the right subcostal margin. Liver function tests revealed elevated enzymatic activities, like GGT, ALP, AST, and ALT, together with increased levels of TBA,
bilirubin (especially conjugated
bilirubin), and decreased levels of total
protein/
albumin and
fibrinogen. Blood levels of
ammonia,
lactate,
cholesterol, and
triglyceride were also increased, and in particular, the serum AFP level reached 319,225.70 microg/L, a extremely elevated value that has rarely been found in practice before. Tandem mass analysis of a dried blood sample revealed increased levels of
free fatty acids and
tyrosine,
methionine,
citrulline, and
threonine as well. UP-GC-MS analysis of the urine sample showed elevated
galactose and
galactitol. The baby was thus diagnosed with suspected
NICCD based on the findings. It was then treated with oral
arginine and multiple
vitamins (including fat-soluble
vitamins A, D, E, and K), and was fed with
lactose-free and medium-chain
fatty acids enriched formula instead of breast feeding. After half a month of treatment, the
jaundice disappeared, and the laboratory findings, including liver function indices, blood levels of
ammonia,
lactate and AFP, were returned to normal level. The baby was followed up for 6 months. It developed well, and the abnormal laboratory findings, including MS-MS and UP-GC-MS analysis results, have been corrected, except a slightly elevated
lactate level sometimes. SLC25A13 gene mutation analysis for the patient revealed a compound heterozygote of mutation 851del4 and 1638ins23 and therefore
NICCD was definitely diagnosed.