Endocrine Abstracts

Background: Turner syndrome (TS) comprises a group of sex chromosome anomalies affecting approximately 15,000 in the UK. TS affects every organ system in the body through haploinsufficiency of genes that are normally expressed by both X chromosomes. Common features include short stature, congenital heart diease and gonadal dysgenesis requiring long-term oestrogen replacement but the adult phenotype extends to excess risk of diabetes, hypertension and hepatosteatosis. UCLH has the longest standing adult TS surveillance clinic and has provided care to 750 women over 20 years resulting in approximately 7,500 clinic visits.

Methods: A retrospective analysis of health surveillance parameters in 583 women with TS and a confirmed karyotype. The most common karyotype groups were compared: monosomy X; mosaic 45,X/46,XX; isochromosome X; mosaic 45,X/46,XY and ring chromosome X. Other karyotype variants were not included. Continuous variables were divided by upper quartiles and karyotype subgroups compared. The resulting binary variables were tested using chi- squared analysis with correction for multiple testing.

Results: Ring chromosome group had an increased prevalence of elevated HbAc1 (P=0.03), GGT (P=0.02) and diastolic blood pressure (P=<0.01), and excess risk of treated depression (P=0.04). Ring chromosome groups showed reduced risk of bicuspid valve and dilated aortic root diameter (P=0.02 and 0.01) compared to monosomy X. 45,X/46,XY had a decreased prevalence of hearing loss and metabolic syndrome.

Conclusions: We have shown novel health risk stratification for adults with TS. The ring chromosome is associated with excess risk for diabetes and hepatic dysfunction with bicuspid aortic disease protection. Y chromosome subtypes were protected from thyroid autoimmunity, hearing loss and had a decreased prevalence of metabolic syndrome. We confirmed the mild phenotype associated with 45,X mosaicism but failed to identify excess risk associated with isochromosome X such as autoimmunity.