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Prevalence of common disease-associated variants in Asian Indians.

Pemberton TJ, Mehta NU, Witonsky D, Di Rienzo A, Allayee H, Conti DV, Patel PI - BMC Genet. (2008)

Bottom Line: In addition, we examined polymorphisms associated with skin pigmentation (SLC24A5) and with the ability to taste phenylthiocarbamide (TAS2R38).Although caution is warranted due to the fact that this US-sampled Indian cohort may not represent a random sample from India, our results will hopefully assist in the design of future studies that investigate the genetic causes of these diseases in India.Our results also support the inclusion of the Indian population in disease-related genetic studies, as it exhibits unique genotype as well as phenotype characteristics that may yield new insights into the underlying causes of common diseases that are not available in other populations.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Genetic Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. trevorp@usc.edu

ABSTRACT

Background: Asian Indians display a high prevalence of diseases linked to changes in diet and environment that have arisen as their lifestyle has become more westernized. Using 1200 genome-wide polymorphisms in 432 individuals from 15 Indian language groups, we have recently shown that: (i) Indians constitute a distinct population-genetic cluster, and (ii) despite the geographic and linguistic diversity of the groups they exhibit a relatively low level of genetic heterogeneity.

Results: We investigated the prevalence of common polymorphisms that have been associated with diseases, such as atherosclerosis (ALOX5), hypertension (CYP3A5, AGT, GNB3), diabetes (CAPN10, TCF7L2, PTPN22), prostate cancer (DG8S737, rs1447295), Hirschsprung disease (RET), and age-related macular degeneration (CFH, LOC387715). In addition, we examined polymorphisms associated with skin pigmentation (SLC24A5) and with the ability to taste phenylthiocarbamide (TAS2R38). All polymorphisms were studied in a cohort of 576 India-born Asian Indians sampled in the United States. This sample consisted of individuals whose mother tongue is one of 14 of the 22 "official" languages recognized in India as well as individuals whose mother tongue is Parsi, a cultural group that has resided in India for over 1000 years. Analysis of the data revealed that allele frequency differences between the different Indian language groups were small, and interestingly the variant alleles of ALOX5 g.8322G>A and g.50778G>A, and PTPN22 g.36677C>T were present only in a subset of the Indian language groups. Furthermore, a latitudinal cline was identified both for the allele frequencies of the SNPs associated with hypertension (CYP3A5, AGT, GNB3), as well as for those associated with the ability to taste phenylthiocarbamide (TAS2R38).

Conclusion: Although caution is warranted due to the fact that this US-sampled Indian cohort may not represent a random sample from India, our results will hopefully assist in the design of future studies that investigate the genetic causes of these diseases in India. Our results also support the inclusion of the Indian population in disease-related genetic studies, as it exhibits unique genotype as well as phenotype characteristics that may yield new insights into the underlying causes of common diseases that are not available in other populations.

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Sampled language groups, their sample sizes, and their geographic origins within India.
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Figure 1: Sampled language groups, their sample sizes, and their geographic origins within India.

Mentions: We have examined the variation of 19 common polymorphisms (Table 1) associated with diseases/traits in a collection of 576 individuals of Indian descent sampled in the United States that represent 14 of the 22 official or scheduled Indian languages as well as one additional cultural group (Parsi; Figure 1). These individuals are part of an expanded cohort that represents 15 groups defined by language and that was used in a previous population-genetic study [10]. The allele frequencies of these 19 common polymorphisms in the Indian cohort can be found in Tables 2, 3, 4; for genotype frequencies see Additional file 2, Tables S1–3.


Prevalence of common disease-associated variants in Asian Indians.

Pemberton TJ, Mehta NU, Witonsky D, Di Rienzo A, Allayee H, Conti DV, Patel PI - BMC Genet. (2008)

Sampled language groups, their sample sizes, and their geographic origins within India.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2267478&req=5

Figure 1: Sampled language groups, their sample sizes, and their geographic origins within India.
Mentions: We have examined the variation of 19 common polymorphisms (Table 1) associated with diseases/traits in a collection of 576 individuals of Indian descent sampled in the United States that represent 14 of the 22 official or scheduled Indian languages as well as one additional cultural group (Parsi; Figure 1). These individuals are part of an expanded cohort that represents 15 groups defined by language and that was used in a previous population-genetic study [10]. The allele frequencies of these 19 common polymorphisms in the Indian cohort can be found in Tables 2, 3, 4; for genotype frequencies see Additional file 2, Tables S1–3.

Bottom Line: In addition, we examined polymorphisms associated with skin pigmentation (SLC24A5) and with the ability to taste phenylthiocarbamide (TAS2R38).Although caution is warranted due to the fact that this US-sampled Indian cohort may not represent a random sample from India, our results will hopefully assist in the design of future studies that investigate the genetic causes of these diseases in India.Our results also support the inclusion of the Indian population in disease-related genetic studies, as it exhibits unique genotype as well as phenotype characteristics that may yield new insights into the underlying causes of common diseases that are not available in other populations.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Genetic Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. trevorp@usc.edu

ABSTRACT

Background: Asian Indians display a high prevalence of diseases linked to changes in diet and environment that have arisen as their lifestyle has become more westernized. Using 1200 genome-wide polymorphisms in 432 individuals from 15 Indian language groups, we have recently shown that: (i) Indians constitute a distinct population-genetic cluster, and (ii) despite the geographic and linguistic diversity of the groups they exhibit a relatively low level of genetic heterogeneity.

Results: We investigated the prevalence of common polymorphisms that have been associated with diseases, such as atherosclerosis (ALOX5), hypertension (CYP3A5, AGT, GNB3), diabetes (CAPN10, TCF7L2, PTPN22), prostate cancer (DG8S737, rs1447295), Hirschsprung disease (RET), and age-related macular degeneration (CFH, LOC387715). In addition, we examined polymorphisms associated with skin pigmentation (SLC24A5) and with the ability to taste phenylthiocarbamide (TAS2R38). All polymorphisms were studied in a cohort of 576 India-born Asian Indians sampled in the United States. This sample consisted of individuals whose mother tongue is one of 14 of the 22 "official" languages recognized in India as well as individuals whose mother tongue is Parsi, a cultural group that has resided in India for over 1000 years. Analysis of the data revealed that allele frequency differences between the different Indian language groups were small, and interestingly the variant alleles of ALOX5 g.8322G>A and g.50778G>A, and PTPN22 g.36677C>T were present only in a subset of the Indian language groups. Furthermore, a latitudinal cline was identified both for the allele frequencies of the SNPs associated with hypertension (CYP3A5, AGT, GNB3), as well as for those associated with the ability to taste phenylthiocarbamide (TAS2R38).

Conclusion: Although caution is warranted due to the fact that this US-sampled Indian cohort may not represent a random sample from India, our results will hopefully assist in the design of future studies that investigate the genetic causes of these diseases in India. Our results also support the inclusion of the Indian population in disease-related genetic studies, as it exhibits unique genotype as well as phenotype characteristics that may yield new insights into the underlying causes of common diseases that are not available in other populations.

Show MeSH
Related in: MedlinePlus