Effects of Adrenal Androgens on Gender-typed Behavior in Girls With Turner Syndrome

Overview

Turner syndrome (TS) is a genetic disorder in which there is loss of all or part of the second X chromosome and occurs in 1/2500 live female births. TS is characterized by short stature and endocrine abnormalities, such as the loss of ovarian function (Gonadal dysgenesis) and estrogen deficiency. The absence of pubertal development is one of the most common clinical features of patients with TS, who should have experienced a sex hormone surge if the hypothalamic-pituitary-gonadal axis was activated normally . Gonadarche and adrenarche are regarded as processes that are independent of each other. The function of adrenal gland is independent of true (central/complete/gonadotropin- dependent) puberty . Adrenal androgen in Turner syndrome shows a wide spectrum, ranging from normal to highly elevated. X-linked genes affect the brain in at least two ways: by directly acting on the brain and by indirectly acting on the gonads to induce differences in specific gonadal secretions (i.e., hormones) that have specific effects on brain development. The changes in brain and behavioral/ cognitive phenotypes in TS individuals may be the result of a direct genetic factor, an indirect hormonal factor, or a combination of the two factors . To evaluate direct effect of X chromosome, a lot of neuroimaging studies have revealed both neuroanatomical and neurofunctional changes in patients with TS. S. C. Mueller (2013) reported that oestrogen deficiency exhibits paradoxical healthy male-like patterns (i.e., a larger amygdala but reduced hippocampal volume). This finding confirms the indirect hormonal effect on the brain that are likely attributed to the effect of androgen on the brain or may be due to active role of estrogen in feminization of brain . The cognitive phenotypes of TS include severe deficits in multiple cognitive domains: visual-spatial ability, mathematical processing, and social cognition. Regarding intelligence, numerous TS studies have a lower performance IQ in contrast to a within-normal verbal IQ in TS individuals . The presence of hypogonadism with normal or may be elevated adrenal function in girls with turner syndrome provide a model to study the hormonal effect of adrenal androgen in absence of estrogen on gender-role behavior. Ehrhardt et al (1970) reported that Women with TS are described as clearly feminine in their behavior and interests . To the best of our knowledge, there have been no previous studies on the correlation between level of adrenal androgen and gender-typed behavior in Girls with TS.