In 1966, one of us (E.J.S.) reported the case of a 19-month-old boy in whom familial hypophosphatemic vitamin D resistant rickets (VDRR) was diagnosed on the first day of life.1 Starting at age 3 months, when his disease was demonstrated to be severe, he received vitamin D in therapeutic doses. Normal growth ensued; at 19 months the child's height was near the 50th percentile, and leg-to-torso ratio was normal.
We were unable to discover other instances in which VDRR was diagnosed and treated before crawling initiates weightbearing at about age 6 months. We therefore recommended that attempts be made to identify and treat infants with VDRR within the first few months of life in order to learn whether deformity and shortness of the legs could be prevented by early treatment. In the present paper, we are summarizing the progress of our patient to age 5 years 8 months. The