Editorial on the Research Topic
Molecular and cytogenetic research advances in human reproductionvolume IIInfertility is a prevalent disorder that affects over 15% of couples worldwide, with various causes such as meiotic arrest due to cytogenetic shuffling, toxins, and other physical factors (1-4). Among the genetic causes of male infertility, chromosomal abnormalities have been reported in approximately 6% of cases, and microdeletions in the Y chromosome account for spermatogenic failure in 5-20% of men with azoospermia (3, 5-8). The most common structural Y chromosome aberrations in infertile men with azoospermia have been reported to be an isodicentric or isochromosome Y, with duplications in the Yp region and deletions in the Yq region, or vice versa (9-12). The human X and Y chromosomes pair at their distal short arms during male meiosis, with the telomeres first approaching each other during the zygotene stage of meiotic prophase (13, 14). As pachytene progresses, a paired segment is formed, and a synaptonemal complex (SC) which, on average, extends to about one-third of the total length of the Y chromosome (15-17).Recently, pathogenic genetic mutations have been identified in individuals suffering from reproductive disorders; these mutations are generally detected in the genes mainly involved in germ cell development and other reproductive processes (18-21). Nevertheless, thousands of functionally relevant genes are expressed in human testes and ovaries, and malfunctioning of even a single gene can potentially cause infertility (22)(23)(24). Although the overall mechanistic contribution of specific genes has been studied in animal models, more attention is now being paid to clinically detected alterations in DNA, which include mutations potentially affecting gene regulatory sequences such as the 3'UTR (25, 26). However, the impact of mutations in gene 3'UTR sequences may not be adequately recognized in current sequencing analyses. This provides a potentially massive gap between Frontiers in Endocrinology frontiersin.org 01
