Genetic predisposition to breath-hold diving-induced hemoptysis: Preliminary study

Area of Science:

• Cardiovascular Genetics
• Environmental Physiology
• Diving Medicine

Background:

• Breath-hold diving-induced hemoptysis (BH-DIH) affects approximately 25% of breath-hold divers (BHD), presenting symptoms like dyspnea, coughing, and chest pain.
• The underlying genetic factors predisposing BHDs to BH-DIH remain largely unexplored.

Purpose of the Study:

• To investigate the association between specific genetic variants in the endothelial nitric oxide synthase (eNOS) and angiotensin-converting enzyme (ACE) genes and the risk of developing BH-DIH.
• To identify genetic markers that could predict susceptibility to BH-DIH in BHDs.

Main Methods:

• A cohort of 108 experienced, healthy BHDs was genotyped for eNOS G894T, eNOS T786C, and ACE insertion/deletion (I/D) polymorphisms.
• Genotype frequencies were compared between BH-DIH-positive and BH-DIH-negative subjects.

Main Results:

• BH-DIH was reported by 22.2% of the studied BHDs.
• A significant association was found between BH-DIH and the eNOS G894T TT genotype (50% prevalence) and eNOS T786C TT genotype (41.2% prevalence).
• The ACE ID genotype showed a higher prevalence of BH-DIH (34.5%) compared to II (0%) and DD (10.5%) genotypes, with the ACE II genotype group exhibiting no BH-DIH episodes.

Conclusions:

• Genetic variants in eNOS (G894T and T786C) and ACE (I/D) significantly influence susceptibility to BH-DIH.
• These genetic factors appear to modulate nitric oxide availability and vascular tone, contributing to BH-DIH risk in breath-hold divers.