Other Names: Hereditary vitamin D-dependent rickets, HVDDR, VDDRII
Inheritance: Autosomal Recessive
Mutation(s): 1 bp deletion (del G)
Affected Gene(s): VDR
Affected Breed(s): Pomeranian

Common Symptoms

Vitamin D-dependent rickets type II (VDDRII) is a rare inherited form of rickets that has been reported in a Pomeranian. VDDRII is caused by a mutation in the vitamin D receptor which is important in maintaining blood calcium levels. Dogs with this disease have decreased amounts of calcium in their blood making them prone to seizures and poorly mineralized, fragile bones. A well-documented Pomeranian affected with VDDRII presented at two months of age with hair loss on the face, chest, abdomen, and thighs. The remaining hair was thin. By 4 to 5 months of age the forelegs were bowed and thicker than normal and the dog had episodes of lameness. Without adequate calcium supplementation dogs with VDDRII will die before 1 year of age.


  • LeVine DN, Zhou Y, Ghiloni RJ, Fields EL, Birkenheuer AJ, Gookin JL, Roberston ID, Malloy PJ, Feldman D. Hereditary 1, 25-dihydroxyvitamin D-resistant rickets in a Pomeranian dog caused by a novel mutation in the vitamin D receptor gene. J Vet Intern Med. 2009 Nov-Dec; 23(6):1278-83. [PubMed: 19909429]