Chromosome polymorphisms in karyotypes from amniotic fluid cell cultures

Area of Science:

• Cytogenetics
• Medical Genetics
• Prenatal Diagnosis

Background:

• Chromosome polymorphisms are variations in chromosome structure.
• Q-banding is a cytogenetic technique used to visualize these polymorphisms.
• Prenatal diagnosis relies on accurate fetal karyotyping.

Purpose of the Study:

• To determine the frequencies of 12 fluorescent chromosome polymorphisms.
• To assess the utility of these polymorphisms in excluding maternal cell contamination in prenatal diagnosis.

Main Methods:

• Scoring of 12 fluorescent chromosome polymorphisms.
• Analysis of Q-banded karyotypes from 108 midtrimester amniotic fluid cell cultures.
• Comparison of maternal and fetal karyotypes in 25 paired cases.

Main Results:

• The most frequent polymorphisms were on chromosome 13 (P=0.458) and chromosome 3 (P=0.426).
• Maternal and fetal karyotype polymorphism patterns differed in all 25 paired cases.
• The technique effectively distinguished maternal from fetal cells.

Conclusions:

• Fluorescent chromosome polymorphism analysis is valuable in prenatal diagnosis.
• This method can reliably exclude maternal cell contamination and outgrowth.
• It ensures the accuracy of fetal karyotype results, especially in cases with female karyotypes.