The cause of more than 60% of spontaneous abortions are chromosomal defects of the embryo or foetus. In order to minimise the risk of pregnancy loss in patients, sensitive diagnostic tools are needed, allowing the accurate diagnosis of the problem. The methods used so far for the analysis of the miscarriage material had a number of limitations. According to experts, the use of innovative DNA next generation sequencing technology allows obtaining a lot of valuable information from tissues which are difficult to analyse.
Embryo death, pregnancy loss or premature birth often occur as a consequence of the presence of genetic errors in the child growing in the woman’s womb. In most cases there are abnormalities in the number of chromosomes, so-called aneuploidies. They result in the occurrence of, among others, Down syndrome, Turner syndrome, Klinefelter’s syndrome, Patau syndrome and many other, most often fatal defects. Performing the appropriate tests and determining the cause of the disorder allows the use of the treatment which will allow the couple to have healthy babies.
Unfortunately, in many cases women are not advised to perform the analysis of the miscarriage material, although it can provide data crucial for further proceedings – says Doctor Sebastian Pukszta from the INVICTA Genetic Laboratory. – In addition, when the patient already reports for tests, the sample can be contaminated with the genetic material of the patient herself, which constitutes a significant difficulty. The classic method in such situations failed; new solutions provide much greater opportunities.
The NGS Technique
The INVICTA Genetic Laboratory was the first in the world to introduce the possibility of diagnosing genetic causes of miscarriage using the NGS (Next Generation Sequencing) technique. The iMGE (INVICTA Miscarriage Genetic Evaluation) Test detects all possible chromosome abnormalities and enables accurate analysis of the supplied material. In this way, precise and reliable results can be obtained. So far, the diagnosis of the miscarriage material was based mainly on the classical karyotyping technique. It required establishing a culture of live cells from the collected sample before the DNA test. The time and conditions of sample collection, as well its transport contributed to the difficulties with delivering a good quality sample. Often it was impossible to get a clear result. The next-generation sequencing (NGS) uses semiconductor chips for translating chemically encoded genetic information directly into digital information. This is an extremely accurate tool that allows identifying any genetic variation.
What does the test consist in?
The first step is to get the test material in hospital. The doctor should prepare a preparation (tissue sample in saline or a paraffin block) and pass it to the lab. The iMGE Test applies special shipping kits that facilitate this process. When the sample arrives to the laboratory, it is pre-evaluated (macroscopically and microscopically) by a pathomorphologist. The specialist isolates the most valuable fragments and forwards them for further analysis. The material in the form of the so-called isolate then gets to the laboratory of molecular biology, where DNA sequencing is carried out using the NGS technique. In its framework, inter alia, the degree of potential contamination of the sample material with the maternal DNA, the so-called testing for MCC (Maternal Cell Contamination) is carried out. In most cases, if the supplied material has been collected correctly, despite the presence of some genes of the woman, it can be assessed accurately whether the miscarriage was caused by genetic factors. Sometimes it is necessary to sample also the maternal DNA.
When should the test be carried out and what are its advantages?
The optimal solution would be the specialist diagnosis of each miscarriage – it would allow physicians to exclude the genetic background of the problem and to take any potential appropriate action. Definitely the test should be recommended for patients who experienced several miscarriages, women who have experienced difficulties with conceiving and women aged 35 and more who miscarried – says Professor Krzysztof Łukaszuk, Head of the INVICTA Fertility Clinics.
Obtaining the result confirming the presence of genetic abnormalities in the miscarriage material is one of the indications for further diagnosis of potential parents, as well as for considering preimplantation testing. The specialist PGS and PGD diagnosis carried out as part of the in vitro programme allows for the analysis of the genetic material of the embryo, even before its transfer to the woman’s uterus. For many couples, this is the only chance for healthy babies.