IL1B and endometriosis: IL1A and IL1B function in a feedback loop with NFκB signaling[24] and have been proposed as the likely causal risk genes at chromosome 2q14.1, a locus associated with endometriosis across multiple populations.[25, 26, 27] Endometriosis risk variants lie around 2 kb centromeric to the promoter of interleukin 1A.