Required for assembly and function of cilia and flagella (PubMed:26224312). Expressed at high level in the testis and at a low level in the lung and brain. Deficient mice shown hydrocephalus, male infertility, and accumulation of mucus in the sinus cavity. The male infertility is due to severe defects in spermatid flagellar formation. Belongs to the CFAP54 family.