Endocrine Abstracts

A 21-year old woman was referred to endocrinology outpatient with sparse hair on scalp, eyebrows, eyelids, and body since birth, short stature, bone pains, proximal muscle weakness, and recurrent fractures of long bones. She was a product of second-degree consanguineous marriage and was eldest of two siblings. Her younger brother aged 16-years had similar complaints.

Clinically she had alopecia universalis, short stature, hypotonia, proximal muscle weakness, deformed pelvis, genu-varum, malunited fractures of shaft femora, and both bones left forearm. A wrist radiograph taken at two years of age had shown changes of rickets. She was earlier treated with herbal medicines and for past six months with calcium and calcitriol with poor response. Haemogram, serum creatinine, serum sodium and potassium were normal. Other relevant laboratory investigations revealed -serum calcium 1.96 millimol per litre (2.2-2.6), phosphate 1.2 millimol per litre (1.4-2.2) alkaline phosphatase 3068 international units per litre (145-320), 25 hydroxy-vitamin D 230 nanomol per litre (25-85), 1, 25 dihydroxy vitamin D three 1467 picomol per litre (40-105), parathyroid hormone 58 nanogram per litre (10-65). This was consistent with the clinical diagnosis of hereditary vitamin D-resistant rickets (HVDRR) or vitamin D-dependent rickets type two (HVDDR II).

Cause of HVDRR is generalized resistance to 1,25 dihydroxy vitamin D three due to mutations in the gene for the vitamin D receptor. Major clinical findings are hypocalcaemia and rickets. The rickets is severe and is exhibited within months of birth. Patients suffer from bone pain, muscle weakness, hypotonia, occasionally convulsions from hypocalcaemia, growth retardation and severe dental caries. . Many children with HVDRR have sparse body, and scalp hair.