SUN-041 Estrogen Pharmacogenetics in Patients with Turner Syndrome

Background: Turner syndrome (TS) is a disorder characterized by complete or partial absence of the second sexual chromosome and the most commonly found abnormalities are short stature and gonadal failure. Most TS patients need estrogen replacement but individual outcomes on uterine volume, breast development and vertebral bone density are highly variable. To our knowledge, the impact of polymorphisms in estrogen receptor 1 (ESR1) over the variability in the development of secondary sexual characteristics and in adult height has not yet been evaluated in TS patients. Objective: To investigate the association among five ESR1 polymorphisms (rs543650, rs1038304, rs2046210, rs2234693 and rs9340799) and breast development, uterine volume, vertebral bone density, FSH and LH levels and adult height in TS patients. Methods: We selected 80 TS patients receiving adult estrogen dose for a minimum period of one year. Patients who had spontaneous complete pubertal development or who have Y chromosome material in karyotype were excluded from analysis. They were submitted to clinical and laboratory evaluation, pelvic ultrasound, bone densitometry and genotyping of the five chosen ESR1 polymorphisms through real time PCR. These polymorphisms were selected through active search in Pubmed and in GWAS catalogs, based on the following criteria: recurrence in studies, being Tag-single nucleotide polymorphisms (Tag-SNPs) or having a minor allele frequency (MAF) which allowed the present study with the available sample. Results: 61% of patients had 45,X karyotype and their mean target height was 158.9cm. 82% of them were treated with rhGH for 5 years on average and they reached a mean adult height of 149cm. Their average age of puberty onset was 14.4 years old and 10% of them had spontaneous thelarche. Their mean uterine volume was 30.1cc but ranged from 5.9 to 83cc. 91% attained adult breast development (Tanner 5) and 93% had normal vertebral bone mass after correction for height (by using the online calculator from University of Washington: courses.washington.edu/bonephys). Only 15% had FSH and/or LH lower than 10 IU/L in two or more measurements. Considering the ESR1 polymorphisms, all of them were in Hardy-Weinberg equilibrium. Statistical analysis with multiple linear regression showed that none of the studied polymorphisms was able to predict any of the above estrogen therapy outcomes in an isolated manner. Conclusion: We could not find a relationship among the studied ESR1 polymorphisms and estrogen therapy outcomes in patients with TS. However, the high variability in estrogen replacement results suggests that genetic variants play an important role. Other efforts to identify polymorphisms associated to estrogen outcomes may allow for individualization of treatment in TS.