A rare ring chromosome 21 abnormality is associated with azoospermia in two different phenotypically normal cases

Area of Science:

• Genetics
• Reproductive Biology
• Human Molecular Biology

Background:

• Azoospermia, a cause of male infertility, requires etiological investigation.
• Karyotyping is the standard diagnostic method for identifying chromosomal abnormalities.
• Phenotypic, physical, and hormonal examinations were normal in the studied cases.

Purpose of the Study:

• To investigate chromosomal abnormalities in two male cases with azoospermia and infertility.
• To identify potential candidate genes associated with the observed chromosomal abnormality and infertility.
• To explore the genetic basis of male infertility linked to rare chromosomal variations.

Main Methods:

• Spermiogram analysis for azoospermia diagnosis.
• G-banding and NOR staining for karyotyping.
• Subtelomeric FISH and array comparative genomic hybridization (CGH) for detailed chromosomal analysis.
• Bioinformatics, protein, and pathway analyses for candidate gene identification.

Main Results:

• A rare ring chromosome 21 abnormality was detected in both cases.
• No microdeletions were found on the Y chromosome.
• FISH and array CGH analyses characterized the ring abnormality and deleted regions.
• Candidate genes were identified through integrated bioinformatics and pathway analyses.

Conclusions:

• Ring chromosome 21 is a rare finding in male azoospermia and infertility.
• Detailed cytogenomic and bioinformatic analyses are crucial for understanding the genetic etiology of infertility.
• Further research is warranted to elucidate the role of identified candidate genes in male reproductive function.