It is likely that low serum 25(OH)D occurs in CE because of intestinal loss of Vitamin D and its metabolites, which are bound to plasma vitamin D binding protein, as previously suggested.61 It would therefore be plausible to investigate the effects of supplementation of calcitriol (1,25(OH)2D) in dogs with CE that have low serum 25(OH)D. The gene discussed is GC; the disease is cholesteryl ester measurement.