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Published on: March 28, 2017
Distribution of CYP2C19 polymorphism and predicted metabolizer phenotypes in the Indian population: A systematic
Smriti Singh1, Chanchal Goyal2, Tejas K Patel1
1Department of Pharmacology and Therapeutics, All India Institute of Medical Sciences, Gorakhpur, Uttar Pradesh, India.
Abstract:
The distribution of CYP2C19 polymorphisms and associated metabolizer phenotypes varies across populations. There is a lack of large scale pooled data on CYP2C19 polymorphisms and associated metabolizer phenotypes in Indian population. This systematic review and meta analysis aimed to determine the prevalence of CYP2C19 loss of function and gain of function polymorphisms (*2, *3, and *17) and their associated genotype predicted metabolizer phenotypes in the Indian population. A systematic literature search was conducted in electronic databases to identify relevant studies reporting CYP2C19 polymorphisms in individuals of Indian origin. Observational studies employing validated genotyping methods were included. Meta analysis was performed using a random effects model with double arcsine transformation to estimate pooled prevalence with 95% confidence intervals (CI). Subgroup analyses were conducted based on geographical regions of India, and heterogeneity was assessed using the I2 statistic. A total of 31 studies were included in the analysis. The pooled prevalence of the CYP2C19*2 allele was 32% (95% CI: 28%-37%), with the highest prevalence observed in South India. The CYP2C19*3 allele was rare, with a pooled prevalence of 1% (95% CI: 0%-1%). The gain of function allele CYP2C19*17 showed a prevalence of 17% (95% CI: 13%-21%), with the highest frequency in North India. The pooled prevalence of poor metabolizers was 16% (95% CI: 11%-22%), whereas ultra rapid metabolizers accounted for 12% (95% CI: 4%-24%) of the population. Substantial regional variability in allele frequencies and metabolizer phenotypes was observed. The distribution of CYP2C19 polymorphisms and metabolizer phenotypes shows considerable regional variability within the Indian population.
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