Prenatal karyotype results from 2169 invasive tests

Area of Science:

• Genetics
• Prenatal Diagnostics
• Medical Science

Background:

• Foetal karyotyping is a standard diagnostic tool for common genetic syndromes.
• Emerging molecular methods like FISH, MLPA, and QF-PCR offer rapid prenatal testing but have limitations for rare chromosomal abnormalities.
• Chromosomal microarray analysis provides higher resolution and is recommended as a first-line genetic test in prenatal diagnosis.

Purpose of the Study:

• To evaluate the ongoing validity and performance of foetal karyotyping in prenatal diagnosis.
• To assess its effectiveness in a large cohort of pregnant women with elevated risk for chromosomal aberrations.

Main Methods:

• Analysis of 2169 foetal karyotypes from two university prenatal diagnostic centers in Lodz, Poland.
• Karyotyping was performed following positive screening results or detected fetal abnormalities via ultrasound.

Main Results:

• A total of 205 (9.4%) abnormal foetal karyotypes were identified.
• Rare chromosomal aberrations, including translocations, inversions, deletions, and duplications, were found in 34 cases.
• A marker chromosome was detected in five cases.

Conclusions:

• Approximately one-third of detected chromosomal abnormalities were rare types, not the common trisomies 21, 18, or 13.
• Many of these rarer aberrations are undetectable by current rapid molecular methods.
• Foetal karyotyping remains an indispensable component of comprehensive prenatal diagnosis.