FHL5 and Azoospermia: In the case of the CREM cofactor ACT, studies in infertile patients with azoospermia or oligozoospermia have identified specific single nucleotide polymorphisms (SNPs) resulting in amino acid changes in the ACT coding region, that, combined to the haplotype 204G-211V-243R-12065G, reduce the interaction between ACT and CREM by 45%, as observed in an in vitro double hybrid test [63].