MONDO_0019642 (vitamin D-dependent rickets, type 2) can be described as follows. Hypocalcemic vitamin D-resistant rickets (HVDRR) is a hereditary disorder of vitamin D action characterized by hypocalcemia, severe rickets and in many cases alopecia. Also known as: HVDRR, VDDR II, VDDR2, VDRR II, hereditary 1,25 dihydroxyvitamin D-resistant rickets with abnormal Vitamin D receptor, hereditary vitamin D-resistant rickets, hypocalcemic vitamin D-resistant rickets, vitamin D dependent rickets 2.