Polymorphic variant rs1739843 of heat shock protein beta-7 (HSPB7) gene and its relationship with on clinical profile and outcomes in patients with hypertrophic cardiomyopathy (results of a 10-year follow-up)

Aim. To determine the impact of polymorphic variant rs1739843 of the HSPB7 gene on clinical profile and outcomes in patients with hypertrophic cardiomyopathy (HCM). Material and methods . The study population consisted of 108 patients with HCM ≥45 years old. The control group included 192 healthy donors. The design of the study included an assessment of the clinical course, determining the outcome of HCM using a new methodological approach proposed by Rowin EJ, et al. (2017). Polymorphic variant rs1739843 of the HSPB7 gene was genotyped by allele-specific real-time polymerase chain reaction (PCR) assay. Results. It was found a significant increase in frequency of TT genotype of rs1739843 of the HSPB7 gene in patients with HCM — 20,4%, compared with control group — 4,2% (ТТ: ТС+СС, odds ratio (OR) =5,88, 95% confidence interval (CI) =2,52-13,75, p<0,001). High prevalence of CC genotype of rs1739843 of the HSPB7 gene was observed in control group — 80,2% vs 31,5% in HCM group (CC: ТС+TT, OR=0,11, 95% CI=0,07-0,19, p<0,001). The allele frequency (С:Т) also differs between HCM and control groups — 55,6:44,4% in HCM vs 88,02:11,98% in control group (OR=5,88, 95% CI=3,91-8,85, p<0,001). It was also found a significant increase in frequency of TT genotype and T allele of rs1739843 of the HSPB7 gene in HCM patients with oligosymptomatic HCM course — 16,7%, compared with control group — 4,2% (ТТ: ТС+СС, OR=4,60, 95% CI=1,63-12,99, p<0,001). HCM patients ≥45 years old showed a significant increase in T allele frequency in cases of presence of 2 (FC III-IV CHF (chronic heart failure)+AF (atrial fibrillation), 18,8% vs 6,6%) and 3 adverse pathways (FC III-IV CHF+AF+SCD (sudden cardiac death), 4,2% vs 1,6%). Conclusion. HCM progression along 2 and more adverse pathways in patients ≥45 years old has been characterized with adverse outcome. The T allele and TT genotype of rs1739843 of the HSPB7 gene were more frequent in patients with HCM ≥45 years old, compared with control group. It was also found a significant increase in frequency of TT genotype and T allele of rs1739843 of the HSPB7 gene in HCM patients with oligosymptomatic HCM course, compared with control group. Allele T of rs1739843 of the HSPB7 gene is associated with 2 and more adverse pathways of HCM progression.