Vitamin D dependent rickets type II: late onset of disease and response to high doses of vitamin D.

Vitamin D dependent rickets Type II is a rare autosomal recessive disorder. The disorder is characterized by end organ hyporesponsiveness to vitamin D. Common presentation of the disorder is total body alopecia and onset of rickets during the second half of the first year of life. Patients may display progressive rachitic bone changes, hypocalcemia and secondary hyper-parathyroidism. It is differentiated from vitamin D dependent rickets type I by virtue of response to physiological doses of exogenous vitamin D in the later. Target organ hyporesponsiveness can be overcome by higher doses of vitamin D or its analogues. We report a case of vitamin D dependent rickets type II with onset of rickets at the age of thirteen years without alopecia progressing to marked disability by twenty three years of age. She responded to massive doses of vitamin D with significant clinical improvement after six months of therapy.