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Data from genome-wide association studies suggest multiple polymorphisms associated with steroid response
 Stephen G. Schwartz |
MIAMI — Varying polymorphisms were shown to be associated with steroid response, a presenter here said.
"Two separate studies have identified multiple polymorphisms with highly statistically significant associations with the change in intraocular pressure following injection of triamcinolone," Stephen G. Schwartz, MD, MBA, said at Angiogenesis, Exudation and Degeneration 2012.
According to Dr. Schwartz, the genetic basis for steroid responders has been postulated for decades, and approaches have included investigation of candidate genes and pathway analysis, as well as research conducted in genome-wide association studies (GWAS).
The GWAS pilot study screened 440,000 polymorphisms and found 48 single nucleotide polymorphisms within 41 separate genes that correlated with steroid response. Interestingly, 24 of these genes are expressed in the retina.
"We know that it is probably not a single gene defect or a single gene polymorphism that determines the steroid response. This [data] would imply that it is a combination of perhaps multiple polymorphisms in multiple genes that contributes to this particular phenotype," Dr. Schwartz said.
Notably, the GWAS validation study determined different leading polymorphisms associated with steroid response.
"The problem is, [this study's] top 10 polymorphisms and the top 10 within the original pilot study are not the same 10 polymorphisms. This may be due to a variety of reasons. ... We are trying to reconcile this as we speak," Dr. Schwartz said.
- Disclosure: Dr. Schwartz is a consultant to Alimera and Bausch + Lomb and has intellectual property licensed to IC Labs.