Polymorphisms of Alpha and Beta Estrogen Receptors in Post-Menopausal Women with Posterior Tibial Tendon Dysfunction

Abstract

Category: Basic Sciences/Biologics Introduction/Purpose: Posterior tibial tendon dysfunction (PTTD), the most common cause of flatfoot deformity in adults, is more frequent in the female gender with peak incidence in the sixth decade of life. Multiple risk factors - intrinsic and extrinsic - and associated systemic conditions have been described in the literature. Genetic predisposition secondary to hyperexpression of genes related to hormonal metabolism, particularly the estrogens, may play a role in the pathogenesis of this disease acting in association with behavioral and endogenous risk factors. Methods: 202 female patients over the age of 40 were included in the study (N = 202). They were then divided into 2 different groups (n = 101): cases and controls. We defined as cases postmenopausal women with symptomatic PTTD, diagnosed by clinical and MRI examinations. Females with similar epidemiology, but clinically asymptomatic and with normal MRI evaluation for the posterior tibial tendon were defined as controls. Oral mucosa epithelial cells were collected from the patients and genomic DNA was extracted from the samples. The SNPs for the ER1 (XbaI and PvuII) and ER2 (AluI) genes were assessed by PCR-RFLP. Results: Patients with SNP Xbal genotype xx had 2.38 higher estimated risk (p = 0,029) in developing PTTD, when compared to patients with the other genotypes. No associations were found for the SNP PvuII and AluI. Conclusion: The present study demonstrates that patients with the Xbal single nucleotide polymorphism of estrogen receptor 1 gene have higher risk of developing posterior tibial tendon dysfunction.