Figure 1.

(a) Histopathological section from a biopsy of the left testis of the patient. Hematoxylin eosin staining of formalin‐fixed paraffin embedded sections show seminiferous tubules (STs) with Sertoli cell only. (b) The positions of the variations on USP26 reported to associate with male infertility. Schematic presentation of the catalytic domain (USP domain), the five binding motifs of USP26 protein to AR according to (Dirac & Bernards, 2010) are the numbered gray boxes, the residues of the catalytic triad are shown in black and the residues forming the zinc‐binding motif in the Fingers subdomain are displayed in hatched bars according to ( Ye, Scheel, Hofmann, & Komander, 2009). The mutations reported not to affect enzymatic activity are marked by ^$ and ^¶ according to (Zhang et al., 2015) and (Liu et al., 2018) respectively and the mutations reported not to affect AR signaling are marked by ^¥ according to (Ma et al., 2016). The mutation R344W affects AR function according to (Ma et al., 2016), mutation Q156H affects enzymatic activity according to (Liu et al., 2018) and variations V154I, S600F, and synonymous S131S, Q750Q, and P757P were not tested. Our newly identified mutation is marked by star. (c) Evolutionary conservation in the region of the USP domain containing the mutation