Figure 2.

Representation of the genes linked to different kinds of asthenozoospermia and the typical phenotype of each kind. In other types of asthenozoospermia, the typical phenotype of four types of asthenozoospermia and related genes are shown, including PCD-related axonemal defects, primary defects from mitochondrial sheath, defects from annulus, and defects of ion channels. In MMAF, four main mechanisms are given, including defects from axoneme structure, defects from peri-axoneme structure, defects in IMT or IFT, and defects in centriole assembly. PCD: primary ciliary dyskinesia; MMAF: multiple morphological abnormalities of the sperm flagella; IMT: intra-manchette transport; IFT: intra-flagellar transport.