Abstract

Extract: Dear Editor, Pituitary gigantism is caused by chronic growth hormone (GH) hypersecretion by a pituitary lesion before epiphyseal fusion. Genetic causes have been identified in nearly 50% of patients with pituitary gigantism, with germline mutations in the AIP gene being the most frequent cause (Rostomyan et al. 2015). Recently, a new form of pituitary gigantism, X-linked acrogigantism (X-LAG), was described (Trivellin et al. 2014). X-LAG is due to chromosome Xq26.3 duplication and GPR101 is the disease-associated gene (Trivellin et al. 2014; Iacovazzo et al. 2016). X-LAG is characterized by of mixed GH/prolactin-secreting pituitary macroadenomas and/or hyperplasia in early childhood (Beckers et al. 2015). X-LAG typically occurs sporadically in females, but somatic mosaicism also occurs in males; familial mother-to-son transmission of the Xq26.3 duplication has been reported in three familial isolated pituitary adenoma families (Trivellin et al. 2014; Daly et al. 2016; Gordon et al. 2016; Iacovazzo et al. 2016). The clinical presentation of X-LAG syndrome differs from other genetic forms of pituitary gigantism (Rostomyan et al. 2015) and many well-known historical cases of gigantism share the clinical characteristics of X-LAG syndrome (Beckers et al. 2015; Rostomyan et al. 2015). If untreated during childhood X-LAG leads to established extreme gigantism (>1.9 meters) before puberty (Daly et al. 2016) ...