Is this project suitable for me?
This project is designed to be a one-year project for a pre-graduate medical student or M.Sc. student with an interest in immunology, particular molecular immunohematology and non-invasive prenatal diagnostics. The majority of the work will consist of laboratory experiments, so an interest in laboratory research is required, but experience is not needed.
The discovery of cell free fetal DNA (cffDNA) in maternal plasma of pregnant women in 1997 has led to the development of non-invasive testing for fetal traits absent from the mother and today non-invasive prenatal RHD typing are run routinely on all pregnant RhD negative women in several countries. Similarly, fetal genotyping for K (kell) and Rh C,c and E on cffDNA is offer in a diagnostic routine settings to pregnant women lacking these antigens on their RBC . All these protocols use real-time PCR looking at difference between alleles based on single nucleotide polymorphism (SNP). Recently, the determination of fetal KEL1 or KEL 2 blood group was also shown using next generation sequencing.
The average fetal fraction of cell free DNA in maternal plasma are in the range of 10-13.4 % in week 10-21 of gestation but there is large variation and 2 % of pregnant women only possess <4 % cffDNA which could impose a problem for correct determination of fetal blood grouping. An increment of the fetal fraction from maternal plasma could ensure more correctly blood group typing. Studies have shown that the cell free DNA varies in size and that cffDNA are <300 bp, whereas cell free maternal DNA are >300 bp, making it possible to select cffDNA by size selection.
Aim of the study
The aim of this study is to set a method for enrichment of ccfDNA from maternal plasma using size selection and to use the purified ccfDNA to determine genetically the blood grouping of the fetus.
- Enrichment of cffDNA.
- Next generation sequencing of cffDNA using targeting sequencing based on blood grouping.
- Use the method in clinical setting and comparing the fetal, maternal and paternal blood grouping.
Assistant Professor Marianne A. Jakobsen, Department of Clinical Immunology, Odense University Hospital.