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Related to pseudohypoparathyroidism: pseudopseudohypoparathyroidism
a hereditary condition clinically resembling hypoparathyroidism, but caused by failure of response to, rather than deficiency of, parathyroid hormone; it is marked by hypocalcemia and hyperphosphatemia and often by short stature, obesity, short metacarpals, and ectopic calcification. Mental retardation, cataracts, tetany, and convulsions may also occur.
A disorder resembling hypoparathyroidism, with high serum phosphate and low calcium levels but with normal or elevated serum parathyroid hormone levels; the defect is due to lack of end-organ responsiveness to parathyroid hormone. There are two types: type I shows lack of renal tubular response to exogenous parathyroid hormone with increase in urinary cAMP, type Is has type I skeletal defects (syn Albright hereditary osteodystrophy), and type II is associated with a defect at a locus after cAMP production. X-linked dominant inheritance caused by mutation in the gene encoding guanine nucleotide-binding protein α-stimulating activity polypeptide 1 (GNAS1), which regulates adenyl cyclase on chromosome 20q. Compare: thyrotropin resistance.
pseudohypoparathyroidismEndocrinology A hypoparathyroid-like state–hypocalcemia, hyperphosphatemia due to end-organ resistance to PTH by bone and kidney, with a loss of renal tubule response to PTH, accompanied by ↑ PTH secretion and parathyroid gland–PG hyperplasia; despite excess PTH secretion in response to hypocalcemia by a normal or hyperplastic PG, the condition is associated with a 2º hypocalcemia-induced ↑ in parathyroid function–administration of pharmacologic doses of PTH normally results in ↑ urinary phosphate excretion and ↑ cAMP, but not in pseudohypoparathyroidism; the pattern of heredity is unclear, ♂:♀ ratio is 2:1; changes include a round face, dental dysplasia, dry coarse hair, mental retardation
A disorder resembling hypoparathyroidism, with high serum phosphate and low calcium levels, but with normal or elevated serum parathyroid hormone levels; due to lack of end-organ responsiveness to parathyroid hormone.