Congenital heart disease (CHD) exhibits a marked male predominance in birth prevalence, yet the genetic mechanisms underlying this sex disparity remain poorly understood. This study investigates the contribution of rare damaging variants on autosomes and the X chromosome to sex differences in foetal CHD. Parents of foetuses with CHD were recruited for the study. Rare damaging variants were identified by analysing whole-exome sequencing data from foetus-parental trios, and their contributions to sex differences were estimated through case-control studies. Functional enrichment analysis was conducted to assess functional differences in genetic variants between sexes. 820 foetal probands with CHD were recruited, including 487 males and 333 females. We identified a significant enrichment of X-linked rare damaging variants, primarily driven by maternally inherited hemizygous variants (MIHVs) in male probands (OR = 1·84, P < 0·05), which accounted for 7·2% of male cases in our cohort. These variants were not found to be enriched in female probands. Additionally, X-linked rare damaging de novo variants (DNVs) were not enriched in either male or female probands (female probands: 1·8% versus female controls: 0·7%, P = 0·6789; no DNVs observed in males). Gene-level variant burden analysis revealed three X-linked CHD candidate genes: DCX, CACNA1F, and MAP3K15. Autosomal rare variants did not show significant differences in variant burdens between sexes. Notably, male probands showed specific functional enrichments in cilia-related pathways for autosomal recessive variants, as well as in chromatin remodelling and nervous system development pathways for autosomal DNVs. Male and female foetal CHD have significantly different genetic landscapes. The enrichment of X-linked rare damaging MIHVs in males provides a genetic explanation for the higher prevalence of CHD in males. This finding highlights the importance of incorporating sex-stratified approaches in clinical diagnostics and research. Natural Science Foundation of China and Key research and development project of Hebei Province.

Objectives: This study sought to echocardiographic manifestations and the related risk factors affecting the prognosis of isolated congenitally corrected transposition of the great arteries (CCTGA). Methods: A total of 143 patients (≥18 years of age) were diagnosed with isolated CCTGA at Anzhen Hospital. The patients were classified as the operation group and the non-operation group depending on whether they had undergone tricuspid valve surgery. The echocardiographic data and follow-up were compared, and the primary outcomes examined were defined as death or heart transplantation. Results: The average age of 143 patients with isolated CCTGA was 39.93 ± 13.50 years. Tricuspid valve surgery was performed in 31 patients with isolated CCTGA, and 112 patients did not undergo tricuspid valve surgery. The incidence of tricuspid valve structural changes in the operation group was 39.1%, and this group had higher numbers of patients with right ventricular diastolic diameter, right ventricular systolic diameter, left atrial dimensions, and regurgitation before surgery compared with the non-operation group (p < 0.05). Follow-up results showed no significant difference in the number of death/heart transplantations, and the incidence of systemic ventricular ejection fraction (SVEF) < 40% between the two groups. The survival rate of the surgery group was higher than that of the non-surgery group, although not statistically significant (p = 0.123). Age, right ventricular end-diastolic diameter, and decreased SVEF at the first diagnosis are independent predictive risk factors for major adverse outcomes. Conclusions: Adult patients with isolated CCTGA may have structural abnormalities in their tricuspid valves. There were no significant differences in the incidence of adverse outcomes, morphological right ventricular systolic dysfunction, and survival between the surgery group and the non-surgery group. However, this study is a retrospective study, and the sample size of the surgical group is relatively small, which may limit the generalizability of the research conclusions. In the future, a prospective, large-scale study will be conducted to evaluate the therapeutic effect of tricuspid valve surgery on such patients.