Fig. 1. Biallelic RAD51AP2 frameshift mutations identified in two patients with unaligned chromosomes in metaphase spermatocytes.

(A) Representative images of testicular sections after hematoxylin and eosin staining. A man who was diagnosed with obstructive azoospermia served as the control. Blue arrowheads indicate metaphase cells with unaligned chromosomes. Green arrowheads indicate the unaligned chromosomes. Scale bars, 50 μm. (B) Sanger sequencing chromatograms of RAD51AP2 frameshift mutations in genomic DNA from the patients. Arrowheads indicate the mutation sites. The nucleotides altered after the site of mutation are written in blue in the mutant allele. (C) Schematic representation of the positions of the mutations identified from patients in the RAD51AP2 gene and protein. The domain interacting with RAD51 is indicated by the pink box. The mutations in case 241 are indicated by red arrows, and the mutations in case 5809 are indicated by purple arrows.