Venkateshwari Ananthapur

Haplotypes of NOS3 Gene Polymorphisms in Dilated Cardiomyopathy

Dilated Cardiomyopathy (DCM) is characterized by systolic dysfunction, followed by heart failure necessitating cardiac transplantation. The genetic basis is well established by the identification of mutations in sarcomere and cytoskeleton gene/s. Modifier genes and environmental factors are also considered to play a significant role in the variable expression of the disease, hence various mechanisms are implicated and one such mechanism is oxidative stress. Nitric Oxide (NO), a primary physiological transmitter derived from endothelium seems to play a composite role with diverse anti-atherogenic effects as vasodilator. Three functional polymorphisms of endothelial nitric oxide synthase (NOS3) gene viz., T-786C of the 5′ flanking region, 27bp VNTR in intron4 and G894T of exon 7 were genotyped to identify their role in DCM. A total of 115 DCM samples and 454 controls were included. Genotyping was carried out by PCR -RFLP method. Allelic and genotypic frequencies were computed in both control & patient groups and appropriate statistical tests were employed. A significant association of TC genotype (T-786C) with an odds ratio of 1.74, (95% CI 1.14 - 2.67, p = 0.01) was observed in DCM. Likewise the GT genotypic frequency of G894T polymorphism was found to be statistically significant (OR 2.10, 95% CI 1.34–3.27, p = 0.0011), with the recessive allele T being significantly associated with DCM (OR 1.64, 95% CI 1.18 - 2.30, p = 0.003). The haplotype carrying the recessive alleles of G894T and T-786C, C4bT was found to exhibit 7 folds increased risk for DCM compared to the controls. Hence C4bT haplotype could be the risk haplotype for DCM. Our findings suggest the possible implication of NOS3 gene in the disease phenotype, wherein NOS3 may be synergistically functioning in DCM associated heart failure via the excessive production of NO in cardiomyocytes resulting in decreased myocardial contractility and systolic dysfunction, a common feature of DCM phenotype.

Endothelin 1 gene as a modifier in dilated cardiomyopathy.

Dilated cardiomyopathy (DCM) is a myocardial disease of unknown etiology with left ventricular dilatation and impaired myocardial contractility leading to heart failure. It is considered to be a multifactorial disorder with the interplay of both genetic and environmental factors. One of the possible genes implicated in DCM is endothelin 1 (EDN1). The genetic variants of EDN1 may be involved in the pathophysiology of DCM hence the entire EDN1 gene was screened to examine for the possible genotypic associations with DCM. A total of 115 DCM patients and 250 control subjects were included in the present study. PCR based SSCP analysis was carried out followed by commercial sequencing. Screening of EDN1 revealed two common and two rare polymorphisms. Allelic and genotypic frequencies were estimated in patient and control groups by appropriate statistical tests. The heterozygotes of insertion variation (+138A) were found to exhibit four-fold increase risk to DCM (OR=4.12, 95% CI 2.10-8.08; p=0.0001). The two rare variants (G>A transition (rs150035515) at c.90 and C>T transition (rs149399492) at c.119) observed in the present study were found to be unique in DCM. The secondary mRNA structures of these variations were found to have less free energy than wild type. The haplotype analysis revealed 4A-T to be risk haplotype for DCM (OR 5.90, 95% CI 2.29-15.25, p=0.0001). In conclusion, EDN1 polymorphisms (+138A, A30A, T40I) appear to play a significant role in the pathogenesis of DCM, as they influence the stability of protein. The increased EDN1 production may lead to constriction of coronary arteries, reducing coronary blood flow which may in turn increase the load on left ventricle, impairing contractility of the heart resulting in a DCM phenotype, an end stage of heart failure.

Association of estrogen receptor α gene polymorphisms with BMD and their affect on estradiol levels in pre- and postmenopausal women in south Indian population from Andhra Pradesh.

BACKGROUND Osteoporosis is a multifactorial disorder with a strong genetic component and ESR1 is suggested as a candidate gene for osteoporosis. Therefore the present study is aimed to investigate the role of ESR1 gene polymorphisms and its influence on estradiol levels and BMD in osteoporotic women of Indian ethnicity. METHODS Four-hundred twenty-seven osteoporotic women and 460 age matched controls were included in the study. ESR1 gene polymorphism was assessed by PCR-RFLP method. Serum estradiol was measured by ELISA. RESULTS The frequency of pp and xx genotypes as well as p and x alleles was significantly high in pre- and postmenopausal osteoporotics when compared to controls (p<0.001). They had low BMD and estradiol levels in comparison with PP and XX genotype individuals (p<0.05). CONCLUSION The ESR1 gene is associated with low bone mass and low estradiol levels in all our study subjects. It is likely that the allele exerts its influence on the bone in early adulthood leading to an increased risk of osteoporosis later in life.

Role of interstitial collagenase gene promoter polymorphism in the etiology of gastric cancer

Background/Aims: Gastric cancer (GC) is a multifactorial disorder mediated by genetic, epigenetic, and environmental risk factors. GC is the most common cancer in India and it is the third prominent cause of cancer death worldwide. A single nucleotide polymorphism (SNP) in the promoter region of interstitial collagenase (MMP-1) gene appears to have an impact on the transcriptional activity and regulation of its expression. Hence, the present study is aimed to evaluate the role of interstitial collagenase gene-1607 1G/2G (rs1799750) promoter polymorphism in the etiology of GC. Patients and Methods: The study included 166 GC patients and 202 control subjects. Genomic DNA was isolated from whole blood samples of the subjects, and the genotyping of interstitial collagenase promoter polymorphism was carried out by polymerase chain reaction-restriction fragment length polymorphism method followed by agarose gel electrophoresis. Appropriate statistical methods were applied to test the significance of the results. Results: The risk factor profile of the patients revealed that male gender, age above 50 years, addiction to alcohol and smoking were the most common risk factors (P < 0.05). There was a significant difference in the distribution of 2G/2G genotype (2G/2G vs. 1G/1G, P = 0.016) and 1G/2G genotype (2G/2G + 1G/2G vs. 1G/1G, P = 0.010) in patient group compared with that of the control subjects. Conclusion: The present study provides indirect evidence for the role of interstitial collagenase gene 1G/2G promoter polymorphism in the etiology of GC in South Indian population.

miRNA regulation during cardiac development and remodeling in cardiomyopathy

miRNAs have been found to play a major role in cardiomyopathy, a heart muscle disorder characterized by cardiac dysfunction. Several miRNAs including those involved in heart development are found to be dysregulated in cardiomyopathy. These miRNAs act either directly or indirectly by controlling the genes involved in normal development and functioning of the heart. Indirectly it also targets modifier genes and genes involved in signaling pathways. In this review, miRNAs involved in heart development, including dysregulation of miRNA which regulate various genes, modifiers and notch signaling pathway genes leading to cardiomyopathy are discussed. A study of these miRNAs would give an insight into the mechanisms involved in the processes of heart development and disease. Apart from this, information gathered from these studies would also generate suitable therapeutic targets in the form of antagomirs which are chemically engineered oligonucleotides used for silencing miRNAs.

Role of proteases and antiprotease in the etiology of chronic pancreatitis.

Background/Aim: Chronic pancreatitis (CP) is the progressive and irreversible destruction of the pancreas characterized by the permanent loss of endocrine and exocrine function. Trypsin, the most important digestive enzyme plays a central role in the regulation of all other digestive enzymes. Chymotrypsin, an endopeptidase hydrolyzes peptides at amino acids with aromatic side chains. Alpha-1-antitrypsin is a principal antiprotease which protects the mucosal tissue from the proteolytic effects of trypsin and chymotrypsin by the formation of molar complexes. The present study is aimed at examining the role of proteases (trypsin and chymotrypsin) and anti-protease (α1-anti-trypsin) in the etiopathogenesis of chronic pancreatitis. Patients and Methods: A total of 90 CP patients and 110 age and sex matched controls were considered for the study. Serum trypsin, chymotrypsin and α1-anti-trypsin levels were determined prospectively in CP patients and compared to healthy controls as described previously. Results: The mean activity of trypsin were found to be increased in CP patients (X ± SD = 0.82 ± 0.838) in comparison to normal control group (X ± SD = 0.55 ± 0.328), (P = 0.001). Chymotrypsin activity were also found to be elevated in CP patients (X ± SD = 0.63 ± 0.278) in comparison to control group (X ± SD = 0.39 ± 0.295), (P = 0.0001). The mean α-1-anti-trypsin activity were found to be lowered in CP patients (X ± SD = 0.42 ± 0.494) in comparison to control group (X ± SD = 0.67 ± 0.465), with the variation being significant (P = 0.0003). Conclusion: The findings suggest an imbalance in the synthesis and degradation of proteolytic enzymes and antiprotease indicating an altered aggressive and defensive role in the pathogenesis of chronic pancreatitis.

Association of ER-α Gene PvuII Polymorphism with Ovarian Cancer

BACKGROUND Ovarian cancer is the most common cancer among women worldwide. Estrogen plays an important role in follicle formation and maturation of oocyte via its receptor (ER). It has a special interest as their protein levels are always elevated in premalignant and malignant cancer cells and are over expressed in different tumors with a favourable prognosis. The present study is aimed to evaluate the role of ER-α gene ( rs2234693) PVUII polymorphism in the etiology of ovarian cancer. MATERIALS AND METHODS A total of eighty clinically and histopathologically confirmed ovarian cancer patients and 100 healthy control subjects were included in the present study. Demographic details along with blood samples were collected from all the subjects. DNA was extracted, amplified and genotyped for ER-α gene PVUII polymorphism by PCR-RFLP method followed by agarose gel electrophoresis. Statistical methods were applied to test for the significance of the results. RESULTS The genotype frequencies revealed 50% of wild homozygotes (PP), 33.75% of heterozygotes (Pp), 16.25% of mutant homozygotes (pp) in the diseased group and 79% of wild homozygotes (PP), 12% of heterozygotes (Pp), 9% of mutant homozygotes (pp) in the control group. There is a significant increase of p allele in patients compared to controls. CONCLUSION The present study thus indicates the possible association of PVUII polymorphism of ER-α gene in the etiology of ovarian cancer.

A novel chromosomal translocation and heteromorphism in a female with recurrent pregnancy loss—a case study

PurposeTo evaluate the clinical, biochemical and cytogenetic analyses of a couple with reproductive failure.MethodsA couple with a history of recurrent pregnancy loss was referred to the Institute of Genetics for cytogenetic evaluation. Chromosomal analysis of the phenotypically normal parents was done to ascertain the role of chromosomal abnormalities and offer appropriate genetic counseling. Further, advanced karyotype analysis by spectral karyotyping was also carried out in the couple and parents of the female partner.ResultsClinical and hormonal profile of the couple revealed normal phenotypes. The ultrasound scan of the female showed normal uterus and ovaries. Chromosomal analysis of the couple revealed a normal 46, XY karyotype in the male spouse, and a unique balanced reciprocal translocation 46, XX, t(12;13) (q13;q33) + 15pstk+ chromosomal constitution in the female partner. Cytogenetic analysis of her parents revealed a similar translocation between chromosomes 12 and 13 in the father and 15pstk+ in the mother. Further, corroboration of the chromosome abnormalities was carried out by spectral karyotyping.ConclusionA unique and novel familial transmission of paternally derived balanced reciprocal translocation and maternally derived heteromorphism in a female with the history of recurrent pregnancy loss was reported as an original investigation.

A Dysmorphic Child with a Pericentric Inversion of Chromosome 8

An 8-year-old boy was referred to our institute with dysmorphic features such as mild lupus, micrognathia, low hair line, hypoplasia, hemi atrophy of left side of the face, abnormal size of ears, hypothenar, hypoplasia of chin, and tongue tie. MRI scan was found to be normal and EEG suggestive of generalized seizure disorder. Cytogenetic evaluation of the proband revealed a pericentric inversion of chromosome 8 with 46, XY, and inv 8 (p11.2; q21.2) karyotype.