Aurora magazine

A team of scientists from Scripps Research has created a genomic technique that facilitates the study of rare diseases. The technique serves in fact to trace the causes, comparing the activity of the maternal and paternal alleles. When levels fall out of the normal range, they insert the allele into the possible causes of the disease. This allows you to narrow the circle and facilitate analysis.

The researchers were looking for a way to identify rare genetic diseases, especially those with early appearance. Standard sequencing methods identify already known genetic mutations, which cause protein deficits. At least half of rare genetic diseases, however, have much more subtle causes. For example, traditional sequencing does not see mutations affecting regions of DNA but not genes.

This is a big problem, as these regions regulate the way genes work. When they do not work properly, the activities of the genes change accordingly and the diseases are manifested. Still, they are invisible mutations for traditional tests. At conception, we inherit a set of maternal alleles and a paternal set. In order for a genetic disease to manifest itself, it is almost always necessary that the anomaly is present in both alleles.

This does not apply to many rare genetic diseases, which also occur with only one anomalous allele. To identify them, the team analyzed the activities of all pairs of alleles. Couples with a strong gradient between one allele and the other are the probable causes of the disease. To test the technique, the researchers used it on patients suffering from rare muscular dystrophies. Thanks to the methodology, they identified all areas of DNA related to the disease. Now the goal is to use the technique on risky newborns, so as to intervene as soon as possible against the disease.

Source: scripps.edu

A team of Indian researchers has developed a neonatal test to measure the risk of adrenoleukodystrophy. The study was published in the journal Clinica Chimica Acta and explains how the procedure works. Adrenoleukodystrophy is a genetic disease caused by mutations in the ABCD1 gene.

The malfunction causes the accumulation of fat molecules known as "very long chain fatty acids". Accumulations destroy myelin, the substance that protects nerve cells, and damages the adrenal glands.

The diagnosis of adrenoleukodystrophy starts from the observation of symptoms. After that, we proceed with a blood test that determines the levels of fatty acids and the severity of the disease. Usually the tests identify the C26: 0, C24: 0 and C22: 0 fatty acids. Furthermore, one can also look for molecules called LPCs, which are formed due to accumulations. Both methods are too slow for widespread screening.

A team of researchers from the National Institute of Mental Health and Neurosciences in Bengaluru has created a new neonatal test. The new screening method is faster and more efficient, completely non-invasive. Just a few drops of dried blood are enough to tell whether the child is at risk or not. To confirm its reliability, the researchers tested the test on 28 samples of sick children and 282 of healthy people.

They also compared the results with those obtained from previous tests. The method has proved effective and reliable. The authors of the study hope that the test will therefore be used on all high-risk infants to ensure early diagnosis.

Source: adrenoleukodystrophynews.com

Bisphenol A is a substance known for its negative effects on the endocrine system. Scientists suspect it may reduce sperm count in men, making it more difficult to have children.

A study by the Icahn School of Medicine and Karlstad University casts a new shadow on the substance. Scientists measured the levels of 26 chemicals in the urine of 718 future mothers during the first trimester of pregnancy. Among the substances there was also bisphenol A, contained in the plastic used for plastic packaging.

However, researchers have also found pesticides and phthalates, all of which are harmful to health. Some of these damage the activity of hormones, just like bisphenol. After giving birth, the researchers followed the children up to the age of 7. Children with lower IQ were those whose mothers had higher levels of chemicals in their urine. In the case of males, the results could even drop by 2 points from the average. Exposure to certain substances could therefore damage fetal development.

What's worse is that even minimal exposure could be enough. In addition to bisphenol A, the most harmful substances could be some types of pesticides and detergent components. These latter substances are almost immediately expelled from the body, yet a minimum time would be enough to damage the embryonic development. As a result, women in early pregnancy should avoid contact with the offending chemicals as much as possible.

Source: mountsinai.org

A Michigan Medicine study shows that the odds of having a boy or a girl are not 50/50. On the contrary, there are genes that favor the offspring of one sex or another, also determining their fertility. This at least in guinea pigs: other studies will be needed to see if this is also the case in humans.

The sex of the unborn child is determined by the X and Y chromosomes present in the gametes. The researchers examined the chromosomes of some guinea pigs and found genes related only to the X chromosomes. As they deepened, they identified multiple copies of the genes in question. In order to identify their role, they removed them from a group of guinea pigs using genetic editing techniques. Mice lacking copies of this gene family were more likely to have litters of males. In these cases, the ratio between males and females was around 60-40. Nevertheless, the percentage of sperm carrying the Y chromosome was always the same.

The difference was that the latter swam faster and more straight, gaining a considerable advantage over the other spermatozoa. After this first experiment, the team tried to increase the percentage of females. For this purpose, it has increased the number of copies of X-linked genes. In doing so, the percentage of female puppies has actually increased to 60%.

The family of genes discovered could therefore influence the velocity of sperm carrying this or that chromosome. But there is more. According to the study, the genes in question could also influence male fertility. In fact, by removing the copies of the gene, the researchers increased both the percentage of small males and the cases of infertility. The little ones without genes were in fact incapable of producing spermatozoa.

Source: med.umich.edu