Why is SLC6A4 Not on the Inagene Test

SLC6A4 used to have strong associations, but these have since been downgraded due to failure to replicate results and in some cases conflicting data. We would have liked to have had it on our test as it was well-regarded when we were first designing the pain panel, however we were unable to get accurate genotyping info from two different design strategies. SLC6A4 is difficult to genotype and it is quite possible that the earlier studies suffered from these inaccuracies and that is why they failed replication. It is a short tandem repeat polymorphism (small section of DNA sequence repeated a variable number of times within the gene) and these are very difficult to test for on our system, so even if it had strong associations, I don't think we would be able to add it to our test - although we have not tried exhaustively. We wouldn't put it on the test now, regardless, because of the low quality of association.