AK7 and male infertility: This point is documented with AK7 gene, which loss of function in the mouse induces a PCD phenotype with male infertility and MMAF phenotype [27, 33], while a missense mutation identified in two MMAF brothers, induces the absence of AK7 protein and axonemal defects in the sperm but no protein damage, nor cilia structure and function in respiratory cells from the patient [27].