Hereditary 1,25-dihydroxyvitamin D-resistant rickets : a report of several cases in a kindred

Abstract EN

We report a Bahraini family with five cases of vitamin D resistant rickets and alopecia.

Investigation confirmed the diagnosis of hereditary vitamin D resistant rickets, type II in 2 of the siblings who were fully investigated.

Although we do not have data to support it, we believe all the sibs had the same type of rickets.

Bahrain Med Bull 1996;18(1): Hereditary 1,25-dihydroxyvitamin D resistant rickets (HVDRR), also known as vitamin D-dependent type II rickets, is a rare autosomal recessive disorder1 .

It results from defective response of the target tissues to the active hormonal form of vitamin D [1,25 (OH)2,D3].

The syndrome is characterised clinically by early onset of rickets with hypocalcemia, hypophosphatemia, secondary hyperparathyroidism in the presence of normal or elevated circulating levels of 1,25 (OH)2 D32,3.

Affected patients in half the kindred's show either partial or total alopecia.

The unresponsiveness of the target tissues to 1,25(OH)2 D3 has been proven to result from mutations in the gene encoding the vitamin D receptor (VDR).

These mutations adversely affect the structure and function of VDR for calcitriol.

In this paper we report our findings in 5 siblings from a Bahraini family of consanguineous marriage who presented to us with vitamin D-resistant rickets and alopecia.

The clinical picture and the course of the disease were similar in all the siblings.

However, since not all these sibs were investigated we have chosen to present the clinical profile of only 2 siblings who were investigated in details.

To the best of our knowledge this is the first case of HVDRR from the Arabian Gulf region.