Expert Review 04
QF-PCR in pregnancy loss samples by Dr Helen White
Traditionally, karyotype analysis of pregnancy loss samples has been the gold standard method for evaluating the genetic cause of pregnancy loss. However, this approach is labour intensive, expensive, requires highly trained technical staff and is often unsuccessful due to the high tissue culture failure rate. Several alternative methodologies to karyotype analysis have been used to investigate genetic abnormalities in pregnancy loss. The QF-PCR method is one of them that is now used more widely for the analysis of pregnancy loss samples.
What you'll learn
- Alternative technologies used to investigate genetic abnormalities in pregnancy loss
- How QF-PCR of short tandem repeats (STR) is used in analysis of pregnancy loss samples
- QF-PCR in routine analysis
- Special considerations when working with QF-PCR
Approximately 10-15% of all clinically recognised pregnancies end in spontaneous miscarriage. Chromosome abnormalities are recognised as being a major factor contributing to pregnancy loss and account for about 50% of all spontaneous miscarriages. In those first trimester miscarriages that have a genetic abnormality, 86% have numerical chromosome abnormalities (i.e. trisomies, monosomies and polyploidy), structural abnormalities account for 6% and the remainder (8%) can be attributed to single gene mutations and mosaicism. Identification of these abnormalities can be useful to provide patientswith estimated recurrence risks for future pregnancies. The main utility of chromosomal analysis forpregnancy loss samples is to differentiate the less common structural rearrangements where therecurrence risk may be substantial (e.g. one parent is the carrier of a balanced reciprocal or Robertsoniantranslocation) from the more frequent whole chromosome aneuploidy or polyploidy where the recurrencerisks are lower. Non-genetic factors contributing to pregnancy loss include infection, immunologicaldisorders, maternal endocrine imbalances, abnormal uterine anatomy and thrombophilic disorders.