Idiopathic hypoparathyroidism is an uncommon condition characterised by the absence, fatty replacement or atrophy of the parathyroid glands. It may be familial or sporadic.
Familial idiopathic hypoparathyroidism may be inherited as a sex linked recessive, autosomal recessive or autosomal dominant with variable penetrance.
The sporadic form of the condition is often associated with Addison's disease, pernicious anaemia or premature ovarian failure. An autoimmune basis is suspected. Children are usually affected. They tend to be of short stature with impaired nail and dental development such as enamel hypoplasia and blunted roots. This skin is characteristically dry and chronic candidiasis, malabsorption and osteomalacia are associated. Cataracts and calcification of the basal ganglia are common.
Characteristic biochemical features include hypocalcaemia, hyperphosphataemia, normal alkaline phosphatase (may be relatively low) and reduced urinary calcium excretion. There is increased urinary phosphate and AMP excretion in response to PTH injection.
Autoantibodies to cytoplasmic parathyroid tissue are found in 30-70% of patients with idiopathic hypoparathyroidism (1)
- Felig P et al (2001) Endocrinology and Metabolism, McGraw-Hill.