We take this opportunity to express our view on the recent study published in the International Journal of Stroke which investigated six SNP (13, 19, rs152312, 45, 83, and 87) of PDE4D gene for its possible association with ischaemic stroke in a cohort from southern Australia . Significant association was found for SNP rs152312 and 45, whereas the other four investigated SNP (13, 19, 83 and 87) did not show any significant association. The result is in contrast with the Western Australian study, which reported positive association of SNPs 83 and 87 with ischaemic stroke .
In a similar study done in north Indian population, we investigated the association between two polymorphisms of the PDE4D gene (SNP83 and SNP87) with acute ischaemic stroke . The study population involved 120 subjects including 60 patients of acute ischaemic stroke and 60 age- and sex-matched controls. Both SNP83 and SNP87 of PDE4D gene did not show significant association with acute ischaemic stroke. It is interesting to note that another study from Northern-Central India has shown significant positive association between SNP83 of PDE4D gene and acute ischaemic stroke . However, another study from Southern India did not show any association with SNP87 of PDE4D, but the association with SNP 83 was again positive .
These inconsistent results with the diverse population groups from different countries suggest that the definite role of PDE4D in stroke development remains unresolved . We fully agree with the opinion of the authors that further prospective studies of PDE4D as risk factor for ischaemic stroke in different populations with larger sample numbers are needed to establish the role of PDE4D in ischaemic stroke and its sub-types.