Progressive rickets manifests during the first years of life with poor growth and skeletal deformities. Total body alopecia is present in severe forms of the disease (2/3 of cases). In some cases, skin lesions or epidermal cysts can be observed along with alopecia. The disease presents a broad clinical picture that largely depends on the genotype.
The disease is due to mutations in the vitamin D receptor gene (VDR; 12q13-14) that decrease the receptor's action thereby preventing calcitriol's action. This leads to an impaired intestinal absorption of calcium due to functional vitamin D deficiency. Transmission is autosomal recessive.
