Vitamin D and estrogen receptor genotypes and phenotypes relationship in Turner Syndrome

LILIANA SILVANO, ADRIANA PEREZ, LILIANA MUÑOZ, GABRIELA SOBRERO, ESTEBAN PRETEL , SILVIA MARTIN, ADRIANA BOYANOVSKY, LAURA CASTRO, VALERIA NIEVA, NORI TOLOSA , MIRTA MIRAS

Lyon

Encuentro; 7th Joint Meeting Paediatric Endocrinology; 2005

ESPE

ABSTRACT The risk of osteoporosis and fractures is increased in Turner Syndrome (TS) patients. The decreased bone mineral density (BMD) in this patients will reflects an intrinsic bone defect, due to the missing ?X? chromosomal material, to hormonal abnormalities of the calcium regulating hormones or to a combination of both. AIMS: To determine the vitamin D receptor (VDR) and estrogen receptor (ER) genotypes in TS patients in relation to their karyotypes, clinical phenotypes (minor, mild and severe forms) and BMD. Subjects and methods: 55 TS patients with CA 17.8 ± 6.5 years; range: 5.7? 30.3 were analysed. VDR genotypes were determined by using Bsm I as a re- striction enzyme and ER genotypes using Xba I and Pvu II. Karyotypes were determined by chromosome banding techniques. Lumbar spine and femoral areal BMD were measured by dual-energy X-ray absorptiometry. ANOVA and Fisher Exact Test (FET) or Chi2 were employed. Results: The karyotype 45,X was present in 37 patients and 18 patients pres- ent different mosaicism variants. The distribution of severe phenotypes were significantly different between karyotype 45,X and mosaicisms (43.2% vs 11.1% p= 0.03). VDR genotypes were BB 16.4 %, Bb 61.8 % and bb 21.8 %. ER genotypes were PP 12.7 %, Pp 54.5 %, pp 32.7 % (Pvu II) and XX 14.5%, Xx 40.0 %, xx 45.5 % (Xba I); it was according to the normal female popula- tion from Cordoba with a tendence of major prevalence of bb genotype in TS versus normal control (Odds Ratio 3.53). There was no association among the VDR, ER genotypes and the karyotypes. The frecuency of Bb genotype was significantly minor in patients with severe phenotype than in those patients with mild forms (38.9 % versus 73.0 % p < 0.032). Femoral and lumbar BMD was similar between different karyotypes and it was worse in bb and BB gen- otypes (p<0.001) but showing modification with estrogen treatment. Conclusions: The data suggest a significant association between VDR geno- type and phenotype and this could give evidence in favor of intrinsic bone defects. There are no tables in this abstract.