Production of the hydroxylated metabolites of vitamin D in a neonate with a single hypoplastic-dysplastic kidney.

The ability to produce dihydroxylated metabolites of vitamin D was studied in a term neonate suffering from severe renal insufficiency. The infant died at age 26 days owing to end-stage renal failure and the necropsy examination showed a single dysplastic kidney weighing 1.5 g. At age 2 weeks the serum levels of the dihydroxylated metabolites of vitamin D were found to be normal and a pronounced increase was noted 24 hours after injection of 100 000 IU vitamin D2. The study suggests that during the neonatal period a small renal mass is sufficient to maintain optimal circulating levels of the dihydroxylated metabolites of vitamin D.