Mcm9, also known as Minichromosome Maintenance 9 Homologous Recombination Repair Factor, is a key protein in multiple DNA-related processes. It is involved in DNA replication (such as the assembly of prereplication complexes), meiosis, homologous recombination, and DNA mismatch repair, which are crucial for maintaining genomic integrity [1,3,6].

Mutations in Mcm9 have been associated with several disorders. In humans, homozygous or compound heterozygous pathogenic variants in Mcm9 can lead to primary ovarian insufficiency (POI), Sertoli cell-only syndrome in males, and are also linked to early-onset cancer, mainly in a recessive inheritance pattern [2,4,5]. Mouse models with targeted mutations in genes related to the Mcm9-associated pathway, like Hrob (which recruits the MCM8-MCM9 helicase), result in infertility due to germ cell depletion and meiotic arrest, suggesting a role of the Mcm9-related pathway in gametogenesis [7].

In conclusion, Mcm9 is essential for DNA-related processes like replication and repair. Studies, including those using mouse models, have revealed its significant role in reproductive disorders such as POI and male infertility, as well as in early-onset cancer. Understanding Mcm9 provides insights into the mechanisms of these diseases and may offer potential diagnostic and therapeutic avenues.