FetalDNA Karyotype Plus is one of the most complete levels as a prenatal test: it adds to all the previous investigations the screening of a large number of chromosomal alterations caused by structural rearrangements (which are defined as microduplications / microdeletions) at a resolution of about 7 Mb (for resolutions inferior diagnosis on maternal blood is not obtained, only invasive prenatal diagnosis such as Amniocentesis or CVS should be used, carrying out a specific study with microarrays).
In brief, with the Karyotype Plus level, the numerical alterations of the 23 pairs of chromosomes of the fetus are analyzed (including the trisomies of chromosomes 13, 18, 21 and the anomalies of the sex chromosomes X and Y, also determining the fetal sex on request) and, thanks to a particular bioinformatics evaluation, it is also possible to inspect the internal structure of the chromosomes, with definition of the order of megabases.
FetalDNA Karyotype Plus is also able to broaden the investigation of pathologies with a screening that allows information on the presence of the most important microdeletion syndromes in fetus.
The term microdeletion / microduplications refers to anomalies characterized by the absence of a small chromosomal tract with consequent loss of gene information (microdeletions) or by the addition of supernumerary genomic material (microduplications). Both conditions cause pathologies with complex and variable clinical and phenotypic pictures depending on the chromosome involved, the chromosomal region involved and the size of the microdeletion / microduplication itself.
The main microdeletion syndromes investigated by the FetalDNA Karyotype Plus are listed below:
In this way, if one of these mutations is present in the mother, it will be necessary to investigate whether the fetus is also a simple carrier or, if the father was also a carrier, ran the risk of being affected by Cystic Fibrosis. This happens in 25% of cases if both parents were healthy carriers.
With the FetalDNA Karyotype Plus, the analysis of the maternal gene is carried out through a screening called 1st level which allows to analyze the most common and frequent mutations, managing to identify about 83% of carriers. The estimated frequency, in the Italian population, of healthy carriers (often unaware of being so) is 1 in 25-30, that of affected births is 1 in 2500 – 3000.
Sex of the child available upon request.
In the event that the mother has a negative Rh factor (which can be documented and visible at the time of the FetalDNA request), it is possible to request a free fetal RH analysis.