Patent ID: 7651838

Claim:
A method for prenatal diagnosis of foetal cells isolated from maternal blood, comprising the following steps: a) diluting a sample of maternal blood collected from a pregnant woman between the 5 th and 15 th week of pregnancy in a filtration solution comprising a reagent for fixing nucleated cells and/or a reagent for lysing red blood cells, b) filtering said diluted sample of maternal blood, on a filter, which has a pore size of 8 μm and a pore density in the range of 5×10 4 to 5×10 5 pores/cm 2 , and under an applied filtration pressure, said filtration pressure being in the range of 0.05 to 0.8 bars, whereby epithelial cells are retained onto said filter; c) analyzing the cells retained on the filter for the presence of at least one immunological or cytological marker, which is characteristic of trophoblastic and/or syncytiotrophoblastic cells, to identify trophoblastic and/or syncytiotrophoblastic cells; and individually collecting at least one cell, which has been identified as being a trophoblastic and/or syncytiotrophoblastic cell, whereby a single cell, which is presumed to be of foetal origin, or a collection of single cells, which are presumed to be of foetal origin, is obtained; d) lysing the single cell of step c), or a single cell of the collection obtained at step c), whereby the genome of this single cell is made accessible to amplification primers, e) amplifying the genome of the lysed single cell obtained at step d), whereby a pre-amplification product is obtained from a single cell, f) using the pre-amplification product obtained at step e), both to demonstrate the foetal origin of the single cell, and to carry out the prenatal diagnosis, wherein: i) said pre-amplification product is analyzed for the presence of genetic or polymorphism marker(s), which can, or the allelotyping of which can, be distinguished from the one(s) of a maternal cell genome, by amplification of said marker(s) from said pre-amplification product, whereby said presence demonstrates the foetal origin of said single cell, and ii) if said foetal origin is demonstrated, identifying at least one genetic or chromosomal anomaly of the foetus, or a genotype thereof, by genetic analysis of said pre-amplification product.