PRRC2A deficiency disrupts m6A-dependent RNA processing and meiosis in human spermatogenesis.

The formation of N6-methyladenosine (m6A) is the most prevalent internal RNA modification in eukaryotic transcripts and plays an essential role in spermatogenesis. PRRC2A is an m6A reader that is indispensable for meiotic progression and is essential for maintaining spermatocyte identity during mouse spermatogenesis. However, its contribution to human spermatogenesis remains unknown. In this study, we investigated a man diagnosed with non-obstructive azoospermia (NOA) and two with severe oligozoospermia, all carrying biallelic PRRC2A variants. All patients exhibited impaired spermatogenesis. The patient with NOA showed marked arrest at meiotic metaphase I or delayed entry into metaphase. RNA-seq and m6A-seq data demonstrated that his PRRC2A deficiency was accompanied by altered chromatoid body-associated RNA regulatory architecture and affected histone-to-transition protein exchange during spermiogenesis. Despite the presence of PRM2-positive spermatids, testicular spermatozoa retrieved from the NOA patient failed to achieve fertilization via TESE-ICSI, possibly due to impaired DNA integrity arising from a perturbed histone-to-protamine transition. In the remaining cases, repeated ART attempts resulted in fertilization failure or early embryonic arrest. A successful pregnancy was ultimately achieved only through donor sperm IVF-ET. The concordance between molecular defects and consistently poor fertilization outcomes across independent individuals supports a pathogenic role for PRRC2A deficiency. We suggest that the disruption of an m6A reader compromises meiotic progression, as well as sperm functional competence and fertilization capacity, although the limited sample size precludes formal statistical inference. By linking epitranscriptomic dysregulation to adverse ART outcomes, this study expands the molecular basis of severe male factor infertility and has direct implications for genetic diagnosis, prognosis of fertilization potential, and reproductive counselling.