Ren S, Nguyen L, Wu S, Encinas C, Adams J, Hewison M. Alternative splicing of vitamin D-24-hydroxylase: a novel mechanism for the regulation of extrarenal 1,25-dihydroxyvitamin D synthesis. J Biol Chem. 2005;280:20604-11 pubmed
..that this is due to abnormal catabolism of 1,25-(OH)(2)D by the feedback control enzyme, vitamin D-24-hydroxylase (CYP24)...
Shanmugasundaram R, Selvaraj R. Vitamin D-1?-hydroxylase and vitamin D-24-hydroxylase mRNA studies in chickens. Poult Sci. 2012;91:1819-24 pubmed publisher
..01) and 24-hydroxylase (P=0.04) mRNA in CD4+ cells. In conclusion, the distribution of 1?- and 24-hydroxylase mRNA amounts was similar to mammals, and an immune stimulation altered the amounts of 1?- and 24-hydroxylase mRNA in chickens. ..