Preliminary considerations
Prenatal diagnosis cannot be limited today only to the search of Down syndrome and cannot be exclusively reserved for women over the age of 35. It has enormous potential and can satisfy the desire of parents to know whether their child is suffering from one of the thousands of diseases being investigated.
Prenatal Diagnosis is always and only a responsible choice of the couple.
Although there are very valid screening tests (such as combined ultrasound and bi-tests) and others that are still in the testing stage, such as DNA research on fetal maternal blood, we must say immediately and clearly that they do not offer any certainty.
The pursuit of free fetal DNA in the maternal blood seems to be fairly reliable only for Down syndrome. There is obviously no certainty regarding this statement either.
The current diagnostic potential related to the introduction of very sophisticated genetic techniques, makes it “abstractly” possible to investigate thousands of genetic diseases through the use of molecular karyotypes, genomic analysis through analysis of minimal chromosomal defects (a-CGH), polymerase chain reactions(PCR) and, more recently, by Next Generation Sequencing (NGS).
Ultimately, a couple who now want to know the state of health of their child in the prenatal period must resort to invasive prenatal diagnosis (amniocentesis or CVS) where the quantity of certain information could, in theory, cover all our knowledge on DNA. As will be more fully explained later, this is not ethical!
Despite the fact that in 1978 Italian legislation established that the mother has every right to be informed (if scientifically possible) regarding the state of health of their children, in order to ensure a responsible pregnancy, there are boundaries that we must not cross.
PERFETTONEVER GO TOO FAR TOWARDS THE DANGER OF EUGENETIC DRIFT, WHERE THERE IS THE RISK OF A DESIRE FOR THE PERFECT CHILD
Investigations must be limited to the search for the existence of severe, certain and immediate diseases. They must then search for those defects that can be dealt with immediately after birth through a correction or treatment that improves the quality of life of the unborn.
On the basis of the indications of more recent literature, even in prenatal diagnosis, in addition to conventional cytogenetics, the recent methods in Array – or comparative genomic hybridization (aCGH) which identify the smallest defects in chromosomes, today there is this amazing technique, Next Generation Sequencing (NGS) analysis of the exome (the part of our DNA that builds the protein structure which we are composed of).
Studying the whole exome means studying all of our DNA coding, i.e. the portion of the genetic code that is responsible for the way we are.
There are no more technical limitations. In theory, any fetal anomaly which is genetically determined (from the greatest defects to the rarer syndromes) could now be detected before birth!
Naturally, not everything is useful and ethically acceptable. In fact, one must consider the dignity of the individual!
In addition to obtaining a great quantity of absolutely useless information (we are all unwitting carriers of small genetic defects which do not compromise our existence) we could find, even before birth, what awaits us in life and death.
To avoid this dangerous and obsessive genetic investigation, we exclude all research on the “polymorphisms of susceptibility” for degenerative diseases, for cancer and for those diseases which start late in life. In no way should “drift eugenics” be considered, limiting research to all the information that parents need concerning the “real and substantial” health of their child.
Therefore, we work on those hundreds of genes whose defects or “mutations” determine only known diseases, many of which are even “treatable” if discovered from birth. In this way, a high number of diseases have been identified which represent, considering their frequency of occurrence, almost all of the malformations and congenital anomalies.
NGPD must not exceed the established limits:
> It should not investigate genetic errors that do not result in a well-defined and know clinical outcome.
> It should not investigate SNPs (Single Nucleotide Polymorphisms) which merely indicate a predisposition towards a degenerative disease or cancer.
> It should not investigate diseases which are compatible with a normal or acceptable quality of life, like many disease states such as diabetes, hypertension and metabolic diseases.
> It should not investigate late-onset diseases, such as Alzheimer’s.
NB: Such important prenatal Investigations cannot, however, be carried out without accurate and complete
genetic counseling for parents which indicates not only the diagnostic certainty, but also the uncertainties, doubts and problems that such vast molecular investigations (as well circumscribed in the selection of genes and mutations research) can determine.