Pericentric inversion 9--incidence and clinical significance

Area of Science:

• Cytogenetics
• Human Genetics
• Reproductive Medicine

Background:

• Pericentric inversion of chromosome 9 (inv(9)(p11q13)) is a frequent chromosomal rearrangement, often considered a normal variant.
• Conflicting reports exist regarding its association with adverse clinical outcomes, including subfertility and recurrent abortions.

Purpose of the Study:

• To investigate the incidence and clinical significance of inv(9)(p11q13).
• To evaluate the association between inv(9)(p11q13) and subfertility, recurrent abortions, and other chromosomal abnormalities.

Main Methods:

• Retrospective analysis of 2448 antenatal cytogenetic analyses and 1058 peripheral blood karyotypes over 3 years.
• Identification and characterization of inv(9)(p11q13) cases.
• Correlation of inversion presence with clinical data, including fertility and obstetric history.

Main Results:

• An incidence of 1.2% for inv(9)(p11q13) was observed in the antenatal group and 0.6% in the peripheral blood karyotype group.
• Babies with inv(9)(p11q13) showed no phenotypic abnormalities.
• Among adult patients with inv(9)(p11q13), 36% experienced subfertility; two pediatric cases had associated chromosomal abnormalities (Trisomy 21, del 13q).

Conclusions:

• inv(9)(p11q13) is a common chromosomal variant with no apparent phenotypic impact on newborns.
• A significant association between inv(9)(p11q13) and subfertility in adult patients warrants further investigation.
• The clinical significance of inv(9)(p11q13) may be underestimated, particularly concerning reproductive outcomes.