Misdiagnosis as steatohepatitis in a family with mild glycogen storage disease type 1a.

The manifestations of glycogen storage disease type 1a (GSD 1a) are usually so prominent in childhood that it is readily diagnosed by pediatricians. However, a mild form of the disease may only become apparent during adolescence or adulthood. We observed a brother and sister with subtle manifestations of the disease, which was discovered after the brother's son was diagnosed with typical GSD 1a. The adult siblings never suffered from hypoglycemia, had normal fasting blood glucose and liver transaminases at the time of diagnosis, and were taller than average for Chinese. Their only notable disease manifestations were recurrent gouty arthritis associated with hyperuricemia and hyperlipidemia during adolescence. When diagnosed, the brother had multiple benign and malignant hepatic tumors, and died of fulminant metastatic hepatocellular carcinoma 6 months after liver transplantation. p.M121V/p.R83H and p.M121V/p.M121V genotypic constellations of the G6PC gene were identified in this family. Both siblings were homozygous for the newly identified p.M121V mutation. The infant had compound heterozygous mutations, p.R83H and p.M121V. We recommend that mild GSD should be considered in the adolescents with unexplained hyperuricemia and hyperlipidemia, despite the presence of normal blood glucose levels. This report also reminds us that hepatocellular carcinoma could develop even in very mild GSD 1a patients.