Infertility in a man with oligoasthenozoospermia associated with mosaic chromosome 22q11 deletion

BACKGROUND: A 30‐year‐old oligoasthenozoospermia man was found to have unbalance mosaic translocation between chromosome 22 and four other chromosomes (5, 6, 13, and 15) during the investigations for a couple with infertility for 3 years, which is a rare event in human pathology. METHODS: Classical cytogenetics analysis, fluorescence in situ hybridization (FISH), and chromosome microarray analyses (CMA) were performed on peripheral blood lymphocytes; copy number variation sequencing (CNV‐Seq) analysis was performed on sperm DNA. RESULTS: Classical cytogenetics analysis showed the presence of six cell lines on peripheral blood lymphocytes: 45, XY, der (13) t(13;22),‐22[10]/46, XY, t(13;22)[6]/45, XY, der(15)t(15;22),‐22[4]/46, XY, t(13;22)[1]/45, XY, der(5)t(5;22),‐22[1]/45, XY, der(6)t(6;22)[1]. FISH and CMA performed on peripheral blood cells showed the presence of a 6.9 Mb mosaic 22q11 deletion (approximately 50% of cells); it is unexpected that the phenotypes of this man were merely oligoasthenozoospermia, mild bradycardia, and mild tricuspid regurgitation. CNV‐Seq analysis performed on sperm DNA revealed the rate of 22q11 deletion cells was obviously lower compared with peripheral blood cells. And the frequency of gametes exhibiting a normal or balance chromosomal equipment was above 80% in sperm samples. CONCLUSION: To the best of our knowledge, this report is the first case of a de novo gonosomal mosaic of chromosome 22q11 deletion just associated with male infertility.