AUTHOR=Ma Ao , Zeb Aurang , Ali Imtiaz , Zhao Daren , Khan Asad , Zhang Beibei , Zhou Jianteng , Khan Ranjha , Zhang Huan , Zhang Yuanwei , Khan Ihsan , Shah Wasim , Ali Haider , Javed Abdul Rafay , Ma Hui , Shi Qinghua TITLE=Biallelic Variants in CFAP61 Cause Multiple Morphological Abnormalities of the Flagella and Male Infertility JOURNAL=Frontiers in Cell and Developmental Biology VOLUME=9 YEAR=2022 URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2021.803818 DOI=10.3389/fcell.2021.803818 ISSN=2296-634X ABSTRACT=

Multiple morphological abnormalities of the flagella (MMAF) can lead to male infertility due to impaired sperm motility and morphology. Calmodulin- and spoke-associated complex (CSC) are known for their roles in radial spoke (RS) assembly and ciliary motility in Chlamydomonas, while the role of cilia- and flagella-associated protein 61 (CFAP61), a mammalian ortholog of the CSC subunits, in humans is yet unknown. Here, we recruited three unrelated Pakistani families comprising of 11 infertile male patients diagnosed with MMAF. CFAP61 variants, c.451_452del (p.I151Nfs*4) in family 1 and c.847C > T (p.R283*) in family 2 and 3, were identified recessively co-segregating with the MMAF phenotype. Transmission electron microscopy analyses revealed severe disorganized axonemal ultrastructures, and missings of central pair, RSs, and inner dynein arms were also observed and confirmed by immunofluorescence staining in spermatozoa from patients. CFAP61 and CFAP251 signals were absent from sperm tails of the patients, which suggested the loss of functional CSC in sperm flagella. Altogether, our findings report that homozygous variants in CFAP61 are associated with MMAF and male infertility, demonstrating the essential role of this gene in normal sperm flagellum structure in humans.