Pseudopseudohypoparathyroidism associated with idiopathic Growth Hormone deficiency. Role of treatment with biosynthetic Growth Hormone

Abstract

A case is presented of a prepubertal girl with the characteristic somatic features of Albright’s hereditary osteodystrophy, including severe short stature, cataracts and shortening of all metacarpals and metatarsals and of the second middle hand phalanges, whose diagnosis of pseudopseudohypoparathyroidism (PPHP) was confirmed by laboratory evaluation (normocalcemia, normophosphatemia, normal levels of circulating PTH and normal response to exogenous PTH). Since an isolated idiopathic GH deficiency has been diagnosed at the age of 9.7 yr, by an abnormal GH response to standard provocation tests, a poor spontaneous nocturnal GH secretion and a blunted response to GHRH test, our patient was treated with biosynthetic GH during a 3.5-year period. Although a good improvement of growth velocity was obtained when comparing pretreatment height velocity (4 cm/yr) with growth velocity evaluated during GH treatment (6.6, 6.2 and 5.9 cm/yr in the first, the second and the third year of therapy, respectively), bone age advanced more rapidly than chronological age, so that it is uncertain whether the growth acceleration promoted by GH administration really improved final height, which remained below the third centile. Our patient is the first described case of PPHP associated with idiopathic GH deficiency, and the second report of long-term GH treatment in a subject with PPHP. Further observations are necessary to define the frequency and significance of GH deficiency and the role of GH replacement therapy in pseudohypoparathyroidism-and PPHP-associated short stature.