[Idiopathic hypoparathyroidism (isolated)].

X-linked recessive, autosomal dominant and autosomal recessive types of familial isolated hypoparathyroidism have been reported, and there are a variety of syndromes of isolated hypoparathyroidism in association with other developmental anomalies involving dwarfism, cortical thickening of tubular bones, nephropathy, sensoryneural deafness and lymphedema. The molecular genetic basis of these forms of idiopathic hypoparathyroidism has been investigated recently. Several genetic abnormalities were elucidated; mutations of the parathyroid hormone gene in some families of autosomal dominant and autosomal recessive familial isolated hypoparathyroidism, a defect at the Xq 26-q 27 region on the long arm of the X chromosome in X-linked recessive familial isolated hypoparathyroidism, and chromosomal deletions at 22q 11 in DiGeorge syndrome. Although adult onset idiopathic hypoparathyroidism may be caused by autoimmune mechanism as a part of polyglandular autoimmune syndrome or as isolated hypoparathyroidism, this type of idiopathic hypoparathyroidism is relatively rare in Japan. Etiology of sporadic cases of adult onset idiopathic hypoparathyroidism still remains to be elucidated.