GPT and glycogen storage disease III: Although the prevalence of hepatocellular carcinoma was low in the International Study on GSDIII,25 severe and progressive liver fibrosis has been described at early ages.26 Only one publication describing high fat diet in two GSDIIIa patients documented data on liver transaminases (cases 4 and 5; [9]) Interestingly, we found that ALT concentrations increased in 44% (4/9) of paediatric GSDIII patients, but decreased in all adult GSDIII patients.