Sex, genes and blood pressure

Area of Science:

• Genetics
• Cardiovascular Physiology
• Human Biology

Background:

• Males typically exhibit higher average blood pressures than females throughout life.
• This sexual dimorphism in blood pressure may stem from genetic factors, including sex chromosomes and sex steroid genes.
• Physiological differences between sexes can also influence blood pressure variation within each sex.

Purpose of the Study:

• To investigate sex-related genetic factors influencing blood pressure.
• To analyze data from the Victorian Family Heart Study, including novel findings.
• To examine the relationship between specific genes (AR, ERalpha, SRD5A1, SRD5A2, CYP19) and blood pressure.

Main Methods:

• Multipoint quantitative linkage analysis of the X chromosome.
• Genetic association studies of Y chromosome single nucleotide polymorphisms (SNPs).
• Analysis of SNPs and haplotypes in genes regulating sex steroids (AR, ERalpha, SRD5A1, SRD5A2, CYP19).

Main Results:

• Systolic blood pressure (SBP) showed linkage to an X chromosome region containing the androgen receptor (AR) gene.
• The Y chromosome was associated with diastolic blood pressure (DBP; P=0.03).
• Significant associations were found between Y chromosome haplotypes, AR SNPs, and DBP in males (P=0.01), with a nearly 6 mmHg difference.
• Polymorphisms in SRD5A1 and ERalpha were associated with DBP and SBP in males, respectively.

Conclusions:

• Genes associated with sexual phenotypes appear relevant to normal blood pressure variation, even within sexes.
• These findings suggest a genetic basis for sex-specific blood pressure regulation.
• Further research is needed to confirm these genetic associations and elucidate the underlying mechanisms.