Bi-allelic Mutations in ARMC2 Lead to Severe Astheno-Teratozoospermia Due to Sperm Flagellum Malformations in Humans and Mice

Coutton, Charles and Martinez, Guillaume and Kherraf, Zine-Eddine and Amiri-Yekta, Amir and Boguenet, Magalie and Saut, Antoine and He, Xiaojin and Zhang, Feng and Cristou-Kent, Marie and Escoffier, Jessica and Bidart, Marie and Satre, Véronique and Conne, Béatrice and Fourati Ben Mustapha, Selima and Halouani, Lazhar and Marrakchi, Ouafi and Makni, Mounir and Latrous, Habib and Kharouf, Mahmoud and Pernet-Gallay, Karin and Bonhivers, Mélanie and Hennebicq, Sylviane and Rives, Nathalie and Dulioust, Emmanuel and Touré, Aminata and Gourabi, Hamid and Cao, Yunxia and Zouari, Raoudha and Hosseini, Seyedeh Hanieh and Nef, Serge and Thierry-Mieg, Nicolas and Arnoult, Christophe and Ray, Pierre F


Male infertility is a major health concern. Among its different causes, multiple morphological abnormalities of the flagella (MMAF) induces asthenozoospermia and is one of the most severe forms of qualitative sperm defects. Sperm of affected men display short, coiled, absent, and/or irregular flagella. To date, six genes (DNAH1, CFAP43, CFAP44, CFAP69, FSIP2, and WDR66) have been found to be recurrently associated with MMAF, but more than half of the cases analyzed remain unresolved, suggesting that many yet-uncharacterized gene defects account for this phenotype. Here, whole-exome sequencing (WES) was performed on 168 infertile men who had a typical MMAF phenotype. Five unrelated affected individuals carried a homozygous deleterious mutation in ARMC2, a gene not previously linked to the MMAF phenotype. Using the CRISPR-Cas9 technique, we generated homozygous Armc2 mutant mice, which also presented an MMAF phenotype, thus confirming the involvement of ARMC2 in human MMAF. Immunostaining experiments in AMRC2-mutated individuals and mutant mice evidenced the absence of the axonemal central pair complex (CPC) proteins SPAG6 and SPEF2, whereas the other tested axonemal and peri-axonemal components were present, suggesting that ARMC2 is involved in CPC assembly and/or stability. Overall, we showed that bi-allelic mutations in ARMC2 cause male infertility in humans and mice by inducing a typical MMAF phenotype, indicating that this gene is necessary for sperm flagellum structure and assembly.