Klinefelter syndrome in combination with familial male-limited precocious puberty (clinical case)

Abstract

The article presents the results of a literature review on Klinefelter syndrome combined with familial male-limited precocious puberty and describes a clinical case. Klinefelter syndrome is a form of male hypogonadism, characterized by the presence of an extra X chromosome, small testes, seminiferous tubule dysgenesis, high levels of gonadotropin, low serum testosterone level, underdeveloped secondary sex characteristics and male infertility. Klinefelter syndrome is characterized by extreme heterogeneity of clinical and genetic manifestations. The prevalence of Klinefelter syndrome is 0.1 to 0.2 % in male newborns and increases to 3 to 4 % among infertile men and 10 to 12 % in patients with azoospermia. Currently, it is not known how to treat patients with mild Klinefelter syndrome that remains undiagnosed or is combined with other genetic pathology, including gonadotropin-independent precocious puberty. This disease is caused by an autosomal dominant inherited activating pathogenic variant of the gene encoding the luteinizing hormone/chorionic gonadotropin receptor, which belongs to the family of G protein-coupled receptors. In men, activation of pathogenic variants of this gene causes excessive secretion of testosterone, which triggers early peripheral (precocious) puberty. Treatment recommendations have been developed in part mainly because of the limited number of reported cases, small sample sizes, and short-term outcomes. The presented clinical case is important in view of the possible risk of developing malignant testicular neoplasms in patients with precocious puberty. Therefore, long-term follow-up during and after puberty is recommended. It is of great importance to take into account the aforementioned clinical manifestations in order to made early diagnosis of this syndrome, offer timely genetic counseling to parents, and rehabilitate these patients physically, psychically and socially.