Pericentric inversions. Problems and significance for clinical genetics

Area of Science:

• Human genetics
• Cytogenetics
• Reproductive biology

Background:

• Pericentric inversions (pii) are chromosomal rearrangements with varying incidence and cytogenetic significance.
• Understanding the biological relevance of pii is crucial for genetic counseling and reproductive health.

Purpose of the Study:

• To review the incidence, cytogenetics, and biological relevance of pericentric inversions.
• To analyze the meiotic behavior, phenotypical relevance, and evolutionary significance of pii.

Main Methods:

• Literature review of 251 cases of pericentric inversions.
• Analysis of cytogenetic data, meiotic segregation, and phenotypic correlations.
• Examination of gonadal findings and occurrence of recombinant offspring.

Main Results:

• Identified 96 different pericentric inversion forms, with 18 classified as types.
• Found approximately 1:1 segregation in meiosis, with no statistically significant alterations in fertility, stillbirth, or abortion rates.
• Aneusomic recombinant occurrence in offspring is dependent on the length of inversion segments, being rare for typical inversion types.

Conclusions:

• Pericentric inversions generally do not impact fertility or cause direct clinical symptoms, though rare cases of trisomic mosaics with pii(9) and pii(22) were noted.
• The length of inversion segments significantly influences the risk of aneusomic recombinants.
• Further investigation into the evolutionary role of pii is warranted.