Heat shock protein 70 gene polymorphisms' influence on the electrophysiology of long QT syndrome.

PURPOSE: Long QT syndrome (LQTS) is a rare cardiac disorder caused due to mutations in genes encoding ion channels responsible for generation of electrical impulses. The heat shock protein (HSP)-70 gene, expressed under conditions of stress, plays a cardioprotective role when overexpressed and helps in the proper folding of the nascent proteins synthesized by the cellular machinery. We aimed to identify the role played by HSP-70 gene polymorphisms in the pathogenesis of LQTS. METHODS: Study included 49 LQTS patients, 71 family members, and 219 healthy individuals recruited from an ethnically matched population. Genotyping of the single-nucleotide polymorphisms (SNPs) rs1043618 (HSP-70-1, +190G/C), rs1061581 (HSP-70-2, +1267A/G), and rs2227956 (HSP-70-hom, +2437T/C) was performed by PCR-RFLP analysis, and the results were analyzed statistically at 95 % confidence interval and p ≤ 0. 05. RESULTS: The "C" allele of HSP-70-1 (+190G/C) and "G" allele of HSP-70-2 (+1267A/G) showed strong association with LQTS phenotype. The haplotype group C-G-T consisting of two risk alleles was significantly associated with the disease condition. Multifactor dimensionality reduction analysis further substantiated that the three-allele model influences the outcome of the phenotype highlighting the effect of modifiers in the etiology of LQTS. CONCLUSIONS: As HSP-70 influences the channel assembly and maturation/trafficking of the ion channel proteins, the alleles C of the HSP-70-1 and G of the HSP-70-2 loci and the haplotype group C-G-T could be considered a diagnostic biomarker in the identification of the LQTS phenotype with a potential to affect the progression and modification of the disease phenotype.

Susceptibility Risk Alleles of -238G/A, -308G/A and -1031T/C Promoter Polymorphisms of TNF-α Gene to Uterine Leiomyomas.

BACKGROUND: Uterine Leiomyomas (UL) are non-cancerous single celled mass of uterine smooth muscles distinguished by presence of large amounts of collagen, fibronectin and proteoglycans. Tumor necrosis factor-α (TNF-α), an inflammation inducing cytokine, plays a major role in various disorders of the immune system; is involved in tumor development and progression. It is proposed to study the influence of three functional promoter polymorphisms of TNF-α viz -238G/A, -308G/A and -1031T/C in the development and progression of UL. METHODOLOGY: Study included 146 individuals positive for uterine fibroids and 150 healthy individuals. Genomic DNA was isolated from white blood corpuscles and subjected to PCR-RFLP analysis and Allele Specific PCR (ARMS). The significance of the obtained data in controls and patients was estimated and computed by adopting appropriate statistical tools. RESULTS: In this study an association between TNF-α -1031T/C polymorphism and UL was reported. A significant association of the TC genotype (χ(2) - 14.34; p=0.0008) and the C allele (χ(2) - 5.898 p=0.015) with uterine leiomyomas was observed. Likewise odds risk estimates of 2.56 (95% CI 1.56-4.20, p=0.0007) revealed a significant association of TC genotype and C allele with uterine leiomyomas. CONCLUSIONS: "TC" genotype and "C" allele of rs1799964 (-1031T/C) is associated with higher risks to leiomyomas. The "C" allele of -1031T/C results in an increased expression TNF-α leading to smooth cell proliferation and tumor progression, hence, may be a relevant molecular marker in the identification and establishment of UL.

The genetic bases of uterine fibroids; a review.

Uterine leiomyomas/fibroids are the most common pelvic tumors of the female genital tract. The initiators remaining unknown, estrogens and progesterone are considered as promoters of fibroid growth. Fibroids are monoclonal tumors showing 40-50% karyo-typically detectable chromosomal abnormalities. Cytogenetic aberrations involving chromosomes 6, 7, 12 and 14 constitute the major chromosome abnormalities seen in leiomyomata. This has led to the discovery that disruptions or dysregulations of HMGIC and HMGIY genes contribute to the development of these tumors. Genes such as RAD51L1 act as translocation partners to HMGIC and lead to disruption of gene structure leading to the pathogenesis of uterine fibroids. The mechanism underlying this disease is yet to be identified. The occurrence of PCOLCE amid a cluster of at least eight Alu sequences is potentially relevant to the possible involvement of PCOLCE in the 7q22 rearrangements that occur in many leiomyomata. PCOLCE is implicated in cell growth processes. Involvement of Alu sequences in rearrangements can lead to the disruption of this gene and, hence, loss of control for gene expression leading to uncontrolled cell growth. This can also lead to the formation of fibroids. Though, cytogenetics provides a broad perspective on uterine fibroid formation, further molecular analysis is required to understand the etiopathogenesis of uterine fibroids.