McCUNE ALBRIGHT SYNDROME: AUTOSOMAL DOMINANT TRAIT IN A FAMILY OF EIGHT

Abstract

McCune-Albright syndrome (MAS) is a sporadic
disease characterised by polyostotic fibrous dysplasia,
cutaneous pigmented spots and autonomous hyperfunction
of multiple endocrine systems(1). Somatic activating
mutations in the gene (GNASI) forthe alpha subunit of Gs,
the protein that stimulatescyclic adenosinemonophosphate
(CAMP) formation, has been identified in affected tissue
of individuals with MAS(2). The activation of adenyl
cyclase is part of a signal transduction pathway that
generatescAMP which isan intracellularsecond messenger
causing permeability changes and hormone secretion on
cells with features of MAS.
An example is secretion of thyroid stimulating
hormone (TSH) by theanterior pitbitary, when this hormone
reaches altered thyroid acini cells, with resultant increase
in iodine uptake and increased production of T3 and t4.
hence hyperthyroidism. A rare case ofMAS, presenting as
an autosomal dominant traitthrough four generations in a
family is presented.