Pseudopseudohypoparathyroidism or Albright hereditary osteodistrophy like syndrome 1

Abstract

Introduction: pseudohypoparathyroidism (PHP) is hormone resistance syndrome described for the first time in 1942 by Albright et al. All this patients had high levels of the PTH and specific skeletal deformities which were later termed as Albright hereditary osteodystrophy (AHO). The PTH requires the alpha subunit of G protein for its action. GNAS1 gene encodes the alpha subunit of the G protein and molecular defects in this gene lead to the occurrence of at least four different forms of this syndrome. Pseudopseudohypoparathyroidism (PPHP) is a form of PHP which is characterized by physical features of AHO without any evidence of PTH resistance. Albright hereditary osteodystrophy like syndrome (AHO like syndrome) has some common characteristics with AHO but is not connected with the molecular defect in the GNAS 1 gene. Case outline: we reported the case of the female patient with the phenotypic characteristics of AHO (brachydactyly, short stature, mild degree of intelectual deficit and genu varum) but without any evidence of PTH resistance. PPHP occurs mainly in families with PHP 1a and it is inherited from the father which is not the case with our patient. There is a theoretical possibility that the mutation of the GNAS 1 gene occurred de novo but without genetic testing the 2q37 deletion and AHO like syndrome can not be excluded. Conclusion: in same cases of PPHP the diagnosis of AHO like syndrome should be considered but the only way to make the precise diagnosis is the genetic testing as it was in our case.

Keywords

• pseudopseudohypoparathyroidism
• albright hereditary osteodystrophy
• albright hereditary osteodystrophy like syndrome
• gnas 1 gene