SYCP3 and Azoospermia: For example, impaired chromosome synapsis (marked by synaptonemal complex protein 3 (SCP3) and SCP1) and decreased meiotic recombination (marked by human mutL homologue 1, MLH1, an ortholog of the Escherichia coli Mut L mismatch repair protein) [2-4], were identified in infertile individuals with non-obstructive azoospermia (NOA).