MARK2 and male infertility: Previous studies suggested that disruptions of CAMK4 located on chromosome 5q22.1, SPINK13 located on chromosome5q32 and the testis-specific serine/threonine kinase (TSSK1B) gene mapped to chromosome 5q22.2 were associated with loss of sperm function and human male infertility [8, 9, 26].