Characterization of late-onset citrullinemia 1 in a Korean patient: confirmation by argininosuccinate synthetase gene mutation analysis.
A 16-month old boy was referred to our hospital for evaluation of recurrent generalized tonic clonic seizures. Metabolic evaluation revealed significant hyperammonemia (1,112 microg/dl). Amino acid/acylcarnitine screening using tandem mass spectrometry showed markedly increased plasma levels of citrulline (1,350 microM/l) with undetectable levels of arginine and arginosuccinic acid. Urinary excretion of citrulline was markedly increased (38,617 microM/g creatinine). Brain MRI findings showed diffuse high-signal intensity lesions, that involved gray and white matter in both frontal lobes and insula with edematous changes; these findings were consistent with the acute stage of citrullinemia (CTLN). Mutation analysis of the argininosuccinate synthetase (ASS) gene, in this patient, showed a Gly324Ser mutation in exon 13, and a 67-bp duplication mutation in exon 15 (c.1128-6_1188dup67). The patient was confirmed as having late-onset CTLN1 and treated with anticonvulsants, lactulose enema, protein restricted diet and arginine. Here we describe a case of late-onset CTLN1 in a patient by biochemical analyses and ASS gene mutation confirmation. This is the first report of a Korean patient with late-onset CTLN1 confirmed by ASS gene mutation identification.
Kim
In-Suk
IS
Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
Ki
Chang-Seok
CS
Kim
Jong-Won
JW
Lee
Munhyang
M
Jin
Dong-Kyu
DK
Lee
Soo-Youn
SY
D001124:Argininosuccinate Synthase / Q000235:genetics*; D001921:Brain / Q000473:pathology; D002956:Citrulline / Q000097:blood / Q000652:urine; D020159:Citrullinemia / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D020440:Gene Duplication; D006801:Humans; D007223:Infant; D007723:Korea; D008297:Male; D020125:Mutation, Missense; D012640:Seizures / Q000235:genetics / Q000378:metabolism
D002956:Citrulline; D001124:Argininosuccinate Synthase