A case of adult-onset type II citrullinemia--deterioration of clinical course after infusion of hyperosmotic and high sugar solutions.

BACKGROUND: Adult-onset type II citrullinemia (CTLN2) is an autosomal recessive disorder caused by mutations of SLC25A13 gene encoding citrin and is characterized by recurrent encephalopathy with hyperammonemia. Factors affecting disease progression remain unknown. We report a case with CTLN2, whose clinical course was rapidly worsened by the administration of Glyceol, a hyperosmotic diuretic solution consisting of 10% glycerol and 5% fructose in saline. CASE REPORT: A 34-year-old man was admitted in coma after repeated episodes of altered consciousness. His plasma ammonia level was markedly elevated without any evidence of liver diseases. Brain MRI revealed high signal intensities at the bilateral cingulate gyri and insular cortices, suggesting hepatic encephalopathy. We administered Glyceol. intravenously to alleviate brain edema, however, he developed intractable seizures along with steep increase in plasma ammonia levels (from 808 to 2210 microg/dL) and died. The diagnosis of CTLN2 was confirmed by elevations of plasma citrulline level (384.3 nmol/mL; normal 17-43 nmol/mL) and serum pancreatic secretory trypsin inhibitor (PSTI) (110 ng/mL; normal 4.6-12.2 ng/mL), decrease in hepatic argininosuccinate synthetase activity (5.5% of control), lack of hepatic citrin protein expression and mutations in SLC25A13 gene (compound heterozygote with S225X and Ex1-1G>A).
CONCLUSIONS: Physicians should take CTLN2 into consideration as a differential diagnosis in Asian patients with a history of repeated unconsciousness with hyperammonemia and use D-mannitol but not glycerol to treat brain edema in patients with CTLN2.