A) The pedigree structure shows the segregation of the MSH4 variant (p.P638L). B) H&E staining of histological sections from the testis biopsy of the patient carrying the MSH4 variant. Scale bar on the upper image represents 50 μm and on the lower image 20 μm. C) Sequence alignment of MSH4 protein orthologs, performed by HomoloGene. Red box highlights the Proline that is changed to Leucine in the MSH4 variant, which is highly conserved among species. D) Immunofluorescent staining of histological sections from the testis biopsy of the patient carrying the MSH4 variant using γH2AX (Green), H3S10p (red), and DAPI (blue). Scale bar represents 5μm. Early cells were observed in 100% of the round tubules that were counted. In a striking number of early cells we observed a spotty γH2AX pattern. No XY bodies were observed in the tubules that were counted for this patient. The metaphase density is higher (15.2 metaphases/mm2) than the previously described control group. This indicates that there are meiotic metaphases present in this patient despite the lack of XY bodies. In addition, 60.8 % of the metaphases were positive for γH2AX.