Group-specific component [Gc] levels in chronic liver disease.

Serum Group-specific component (a probable vitamin D transport protein) concentrations have been measured in 72 patients with chronic liver disease. Low mean values were found in groups of patients with cirrhosis and metastatic liver disease. In a group of patients with biliary tract disease the mean value was not significantly different from normal except for seven patients with severe bone disease who were found to have the lowest levels. The mechanism for the reduction remains to be clarified, but low Group-specific component values may play a contributory role in the osteodystrophy of chronic obstructive liver disease.