Three cases of genetic defects affecting sperm tail: a FISH study

Area of Science:

• Reproductive Biology
• Human Genetics
• Spermatozoa Morphology

Background:

• Submicroscopic sperm flagellar cytoskeletal defects are linked to male infertility and reduced sperm motility.
• Genetic sperm defects affecting the entire sperm population can be identified using Transmission Electron Microscopy (TEM).

Observation:

• This study investigated sperm aneuploidy and diploidy in three patients with distinct flagellar anomalies: dysplasia of the fibrous sheath, primary ciliary dyskinesia, and absence of the fibrous sheath.
• TEM confirmed these flagellar defects.
• Fluorescence in situ hybridization (FISH) was used to analyze chromosomes 18, X, and Y in decondensed sperm nuclei.

Findings:

• Patients with dysplasia of the fibrous sheath and primary ciliary dyskinesia showed increased diploidies and sex chromosome disomies, consistent with prior research.
• In the rare case of absence of the fibrous sheath, aneuploidy and diploidy levels were within the normal range.
• These findings suggest a correlation between genetic sperm flagellar defects and meiotic segregation errors.

Implications:

• The data support the hypothesis that genetic defects in sperm flagella are frequently associated with meiotic segregation abnormalities.
• Genetic counseling is recommended for individuals with these sperm defects.
• Further research is needed to fully characterize the involved genes and mutation mechanisms.