Modern views on the genetic determinism of GH-secreting pituitary adenomas (literature review and own data)

Abstract

Background. This article presents a review of the current literature on the role of the genetic component in the etiology and pathogenesis of hormone-active pituitary adenomas secreting growth hormone (GH) and clinically manifesting by acromegaly and/or gigantism (multiple endocrine neoplasia 1 (MEN-1), McCune-Albright syndrome, Carney complex, X-linked acrogigantism (X-LAG), familial isolated pituitary adenoma — FIPA). Materials and methods. To identify mutations in the AIP gene and to verify FIPA, 26 patients of the Ukrainian population (19 women and 7 men) were examined in whom acromegaly was diagnosed in adolescence or young age, and genetic analysis was performed. To determine the genetic determinism in the development of GH-secreting pituitary adenoma and differential diagnosis of FIPA and MEN-1 syndromes by sequencing method (MLPA — ligation-dependent probe amplification), the genes MLPA, P244-C1 were studied involving exons 1–6 MEN1 gene, (MLPA, P017-D1) AIP gene. Results. Among those examined, only two patients had AIP gene mutations. In one patient, genetic screening for MEN1 gene mutation was negative and no clinical symptoms suggestive of McCune-Albright syndrome were detected. A variant heterozygous missense c.714C>G (p.Cys238Trp) was found in the AIP gene. This AIP gene assay is compatible with a genetic predisposition to develop pituitary adenoma. The offspring of this patient has a 50% chance of inheriting this variant, acromegaly, hypersomatotropinemia, MEN-1 syndrome, familial isolated pituitary adenoma. Another patient was diagnosed with MEN syndrome type 1 (Wermer syndrome): insulinoma, parathyroid gland adenomas (2), primary hyperparathyroidism with a heterozygous c.134A>G variant (p.Glu45Gly) found in the MEN1 gene. The presence of the c.l34A>G (p.Glu45Gly) class variant 4 is likely to be pathogenic. The prevalence of this variant in the general population is unknown, so it is very rare. Conclusions. The genetic analysis is appropriate in pediatric and young patients or those with GH-secreting macro/giant pituitary adenoma diagnosed at a young age (under 35), regardless of family history. In patients with a history of a disease, genetic analysis is recommended in any case to identify FIPA and to predict the further course of the disease and the effectiveness of treatment with somatostatin analogues.

Keywords

• acromegaly, hypersomatotropinemia, men-1 syndrome, familial isolated pituitary adenoma, genetic analysis