Association between Interleukin-6 (-174 G/C and -572 C/G) Promoter Gene Polymorphisms and Risk of Intracerebral Hemorrhage in North Indian Population: A Case Control Study.

Background: Interleukin-6 (IL-6), a pro-inflammatory cytokine is involved in various vascular pathologies including stroke. Till date, no studies have been reported for the association between IL-6 gene polymorphisms with the risk of Intracerebral hemorrhage (ICH). Objective: The aim of this present case-control study was to investigate the association between IL-6 (-174 G/C and -572 C/G) gene polymorphisms and risk of ICH in North Indian population. Methods: Genotyping was carried out by using SNaPshot method for ICH patients and 100 age-sex matched ICH free controls. Conditional logistic regression analysis with adjusting multiple demographic and risk factor variables was used to calculate the strength of association between IL-6 (-174 G/C and -572 C/G) polymorphisms and risk of ICH. Results: Hypertension, diabetes, dyslipidemia, smoking and low socioeconomic status were found to be associated with the risk of ICH. The distribution of -174 G/C and -572 C/G genotypes was consistent with Hardy Weinberg Equilibrium (HWE) in the ICH and control subjects. Conditional logistic regression analysis showed a significant association between IL-6 -572 C/G gene polymorphism and the risk of ICH under dominant model (OR=3.7; 95%CI 1.05 to 13.1; p=0.004) and allelic model (OR=2.6; 95%CI 1.1 to 6.2; p=0.01). No significant association was observed for the association between IL-6 -174 G/C gene polymorphism and risk of ICH. Conclusion: Our results suggest that IL-6 (-572 C/G) polymorphism is significantly associated with the risk of ICH in North Indian population. Further prospective studies with large sample size are needed for independent validation.

Spinocerebellar ataxia 7 (SCA7) in Indian population: predilection of ATXN7-CAG expansion mutation in an ethnic population.

Background & objectives: spinocerebellar ataxia 7 (SCA7) is a rare form of neurodegenerative disorder with the clinical manifestation of cerebellar ataxia and retinal degeneration. In this study we describe the clinico-genetic characteristics of nine SCA7 families of Indian origin and cross compare these with other available worldwide studies. Methods: Thirty five individuals from nine SCA7 families were clinico-genetically characterized and CAG repeat distribution analysis was carried out in 382 control DNA samples from healthy controls (derived from 21 diverse Indian populations based on ethnic and linguistic and geographical location). Results: Of the nine families studied, 22 affected individuals and one asymptomatic carrier were identified. The average age at disease onset was 23.4±12.6 yr. The length of expanded CAG ranged from 40-94 with mean value of 53.2±13.9. The main clinical findings in affecteds individuals included cerebellar ataxia, and retinal degeneration along with hyper-reflexia (95%), slow saccades (85%) and spasticity (45%). Analysis of the association of number of CAG repeats with disease onset revealed that <49 repeats were associated with earlier age at onset in South East Asians compared to European populations. Further analysis of CAG repeats from 21 diverse Indian populations showed pre-mutable repeats (28-34) alleles in the IE-N-LP2 population. Six of the nine families identified in this study belonged to the same ethnic population. Interpretations & conclusion: Our results show that presenece of SCA7 is relatively rare and confined to one ethnic group from Haryana region of India. We observed a homogeneous phenotypic expression of SCA7 mutation as described earlier and an earlier age of onset in our patients with CAG <49. The identification of pre-mutable allele in IE-N-LP2 suggests this population to be at the risk of SCA7.