The Impact of Karyotype on Congenital Heart Diseases in Turner Syndrome: A Systematic Review and Meta‐Analysis

It is evident that Turner syndrome (TS) impacts almost all developmental stages of the fetal heart with congenital heart disease (CHD) being seen in 23%-50% of individuals. Although the spectrum of CHDs in TS is well-established, with left-sided lesions predominating, the influence of specific karyotypes on the prevalence and types of CHDs remains incompletely understood. The primary objective of this systematic review/meta-analysis was to quantitatively synthesize the existing evidence on the association between specific karyotypes in TS and the risk of various CHDs. A systematic literature search was conducted through December 2023 to identify studies reporting the prevalence of CHDs in relation to TS karyotype. The quality of the individual studies was assessed using the Joanna Briggs Institute critical appraisal tools for systematic reviews. The overall estimates were pooled using both fixed- and random-effects models. Sensitivity and subgroup analysis were performed. Twenty-five studies were included in the analysis. TS individuals with a 45,X karyotype showed a significantly higher likelihood of bicuspid aortic valve (BAV) (pooled OR, 3.14 [95% CI: 2.49-3.94]), aortic coarctation (CoA) (pooled OR, 4.16 [95% CI: 2.74-6.31]), and partial anomalous pulmonary venous return (PAPVR) (pooled OR, 4.86 [2.31-10.2]) compared with TS individuals with a non-45,X karyotype. In addition, TS individuals with a 45,X karyotype also showed a significantly higher likelihood of BAV (pooled OR, 2.72 [95% CI: 1.62-4.56]) when compared with TS individuals with 45,X/46,XX mosaicism. TS individuals with a 45,X karyotype showed a significantly higher risk of BAV (pooled OR, 2.13 [95% CI: 1.42-3.21]) and CoA (pooled OR, 4.52 [95% CI: 1.58-13.0]) when compared with TS individuals with an isochromosome Xq. A significantly higher likelihood of BAV was also found in 45,X compared to other karyotypes (e.g., 45,X/46,XY and TS karyotypes with ring X chromosome). Some heterogeneity was evident, but publication was low. This meta-analysis confirms a strong association between the 45,X karyotype and increased prevalence of BAV, CoA, and PAPVR in TS. While 45,X/46,XX mosaicism and karyotypes with an isochromosome Xq mitigate risk, the findings emphasize the need for large-scale studies to refine risk assessment and management strategies.