Aurora magazine

There is talk of mosaicism when the same person has cells within him with a different genetic heritage. It is therefore possible that they have a part of healthy cells and a part of cells affected by chromosomal abnormalities. Depending on the case, the condition can also affect particular types of cells, such as those of blood, skin and gametes.

At the basis of mosaicism there is an error in cell division during embryonic development. If the cells affected by the anomaly are few, it is possible that the effects on the individual are limited. If they were the majority, it becomes much more likely to manifest pathologies. For example, it is possible to have Down syndrome, Klinefelter syndrome and Mosaic turner.

The only method to have a reliable diagnosis of mosaicism is genetic testing and prenatal screening tests. The cells of the fetus are analyzed and the presence of cells with chromosomal abnormalities occurs. If successful, continue with further genetic tests. In this way an estimate is made of the number of anomalous cells and, consequently, of the severity of the mosaicism.

The effects of mosaicism vary greatly depending on the severity and the cells involved. In general, it is difficult to predict with confidence the effects of such a condition. A chromosomal abnormality present in most cells is almost equivalent to an abnormality present in 100% of cells. A low percentage of abnormal cells may have no effect on the individual, but have repercussions on his offspring. Current genetic testing and fetal DNA testing can unveil this possibility in time.

Source: nytimes.com

In in vitro fertilization (IVF) it is necessary that the implanted embryos are as healthy as possible. In this way there are more chances that the implant will be successful and that the child is healthy. Even so, the chances of success of the whole process are around 30%.

As maternal age progresses, the number of usable healthy embryos decreases. This leads to a lower rate of implants and a higher rate of spontaneous abortions. All of this causes less chance of success for IVF procedures. But we are sure that the embryos must be impeccable so that the plant is successful. The study in question examined the relationship between mosaicism and in vitro fertilization.

The study involved 77 women who accepted embryo implantation with mosaicism. In fact, the fertilization phase did not give rise to any euploid embryo, without 100% chromosome anomalies. 50% di cellule anormali). ">The researchers divided the embryos according to the degree of mosaicism: low (<50% of abnormal cells) or high (> 50% of abnormal cells).

On 78 implanted embryos, 37 took root. At the end of all, the children born were 24, with a rate of 30%. The positive results concerned embryos with a low level of mosaicism. In fact, we speak of 48.9% of installations against 24.2% of the second group. Also the live birth rate was very different: 42.2% of the first group against 15.2% of the second.

The study showed that in vitro fertilization can be successful even in the case of embryos with mosaicism. For safety, all study participants underwent prenatal screening tests. In the 24 successful cases, the children born were all healthy and free of chromosomal abnormalities.

Since there are few bases, it is possible that the abnormal cells have been eliminated during development. The mechanism will be explored and the researchers advise however to avoid the implantation of embryos with mosaicism, where possible.

Source: medscape.com

Taking paracetamol in pregnancy could affect the fertility of our descendants. This is revealed by a study led by Dr. Rod Mitchell, of the University of Edinburgh. The study is based on similar research, which had already highlighted the possible criticalities of the drug.

Paracetamol has so far been considered a relatively safe drug in pregnancy. Previous studies had highlighted possible negative consequences for female fertility. This study also widens the alarm to male fertility.

Scientists analyzed the effects of paracetamol and ibuprofen on samples of human fetuses and ovaries. Later, they extended the study to pregnant mice. Both types of tests have revealed negative effects on the fertility of offspring, both for females and for males.

In the tissues exposed to one of the two drugs for a week, the number of oocytes and spermatozoa decreased by 40%. As for the guinea pigs, one day of treatment was enough to have the first negative effects. Male offspring had a 17% reduction in spermatozoa. On the other hand, mice exposed to drugs for a week during the prenatal period had a reduction of almost a third.

Ibuprofen and paracetamol could affect prostaglandin molecules, which are essential for ovaries and testes. This would explain why the negative effects on those exposed in the womb of drugs. The effects could however be much longer lasting.

The researchers found that prenatal exposure to paracetamol and ibuprofen could result in epigenetic changes. The changes thus introduced would be inheritable and could also influence the fertility of future generations. For this reason, they advise to take the two drugs only on medical advice and if strictly necessary.

Source: telegraph.co.uk

Exome analysis could become a prenatal diagnostic tool in many cases of suspected skeletal abnormality. This was revealed by a study led by Lyn Chitty of the Great Ormond Street NHS Foundation Trust in London.

Undiagnosed skeletal abnormalities affect about 2-5% of pregnancies. Cytogenetic and microarray prenatal screening can identify about 40%. For other types of anomalies, the diagnosis remains complicated. For this reason, the new study explores the potential of exome sequencing analysis in fetuses and parents.

According to an article published in Genetics Medicine, prenatal analysis of the exome would be able to identify 81% of cases of skeletal dysplasia. If the numbers were confirmed, then there would be a further tool for prenatal diagnosis. In particular, this type of test would be useful in cases of suspected unconfirmed anomalies.

Dr. Chitty's study refers to 19 cases of pregnant British women. The women had undergone invasive prenatal tests, after the ultrasound had identified suspected skeletal dysplasias. Of these, 16 went ahead with sequencing.

The researchers used the Illumina NextSeq500 platform to sequence the parental exome and fetal DNA. In case 12, the parents also sequenced the DNA of the siblings due to the low amount of fetal DNA. Researchers focused on the 240 genes related to skeletal dysplasia. A separate project by the Sanger Institute has confirmed all the results.

In 13 cases, the researchers were able to provide a definitive diagnosis. They uncovered 4 recessive pathologies that the fetus had inherited, 6 dominant de novo variants and 2 pathogenic variants inherited from the mother. The last case was more complex. In the 3 cases left without a certain diagnosis, variants were present whose significance was doubtful.

Source: genomeweb.com