Related Experiment Videos
[Hypocalcemic vitamin D-dependent renal rickets]
Insights
Vitamin D-dependent rickets, a genetic disorder, causes severe bone and mineral imbalances. Treatment with dihydrotaquisterol effectively resolved symptoms in affected siblings.
Area of Science:
- Pediatric Endocrinology
- Metabolic Bone Disease
- Genetics
Background:
- Vitamin D-dependent rickets (VDDR) is a rare genetic disorder.
- It stems from a defect in vitamin D metabolism, specifically the enzyme 25-hydroxy-D1-hydroxylase.
- This defect prevents the formation of the active vitamin D metabolite, 1,25-dihydroxycholecalciferol.
Observation:
- Two siblings with VDDR presented with persistent rachitic manifestations since infancy.
- Biochemical analysis revealed severe hypocalcemia, moderate hypophosphatemia, and elevated alkaline phosphatase.
- Diminished renal tubular reabsorption of amino acids and phosphates was noted, reversible with IV calcium gluconate.
Findings:
- Patients with VDDR exhibited characteristic biochemical and clinical features of rickets.
- Despite high-dose vitamin D, symptoms persisted, indicating a metabolic defect rather than simple deficiency.
- Successful treatment with dihydrotaquisterol normalized clinical, biochemical, and radiological findings within one year.
Implications:
- Dihydrotaquisterol represents an effective therapeutic agent for vitamin D-dependent rickets.
- Understanding the specific enzymatic defect is crucial for targeted treatment strategies.
- Early diagnosis and intervention are vital to prevent severe complications in children with VDDR.
Abstract:
Two siblings, female 10 years old, and male 15 years old, with the diagnosis of vitamin D-dependent rickets were studied. Another sibling, also with the same diagnosis, died of bronchopnemonia at about 7 months of age. Both patients developed rachitic manifestations since the first year of life, which persisted despite the administration of massive doses of vitamin D intermitently. Severe hypocalcemia, moderate hypophosphatemia and elevated serum alkaline phosphatase were the most characteristic biochemical findings. Both patients showed diminished renal tubular reabsorption of amino acids and phosphates. These alterations were reversible during I.V. calcium gluconate administration. The clinical biochemical and X-ray manifestations disappeared completely after one year of treatment with dihydrotaquisterol. Vitamin D-dependent rickets is an autosomal recessive disease, characterized by a hydroxylation defect of 25 hydroxycholecalciferol at the carbon 1 level, due to abscence of 25 hydroxy-D1-hydroxylase. Thus 1-25 Dihydroxycholecalciferol, the active form of vitamin D3 is not formed, resulting in depression of intestinal calcium absorption and reabsorption from the bones.