Still hereditary diseases

The threat of genes

Ganna Rudenko, Jewish.ru

Today, every fourth Jew is a carrier of at least one hereditary disease, and Ashkenazim are twice as likely to get it as Sephardim. This increased danger prompted the American company JScreen to launch a massive campaign to conduct genetic tests for 104 diseases, the most common in the Jewish environment.

There are not as many Jews in the world today as some people think – just a little more than 14 million. For many centuries, this community was closed and categorically did not welcome interethnic marriages, which did not contribute at all to its genetic enrichment. In addition, in the case of the Jews, the "bottleneck" effect was fully manifested: the number of people was significantly reduced during the anti-Semitic persecution, and then restored again, but with a depleted set of genes. All this led to the fact that the Jewish genetic fund simply had nothing to update and its "breakdowns" were reliably preserved, accumulated and passed on.

Naturally, even 100 years ago, it was not easy to fully assess the level of your inherited ill health. Yes, before the wedding, older relatives or matchmakers scrupulously studied the pedigree of a potential groom or bride, paying attention to any physical and behavioral abnormalities. But genetic diseases did not manifest themselves in all carriers, and taking into account the fact that some disorders made themselves felt in infancy (if not in the womb) and quickly led to death or seemed to be a variant of the norm, it was not always possible to understand that there was any problem at all. So there was nothing else to do but to pass the "family" set by inheritance as it is, with all its good and bad codes.

Today, every fourth Jew is a carrier of at least one hereditary disease, and an Ashkenazi is 2 times more likely to get it than any other representative of the Jewish people. And although science today is happy to serve and warn, in our time, too, few people know that some kind of disease is "sitting" in it, and in complete ignorance carelessly passes the baton on. According to statistics, 80% of children with genetic diseases are born to parents who were not even aware that they have some kind of "broken" gene.

In conditions of such "increased danger", Jews should know everything about their genetics in order to choose the right partner or simply be ready for the birth of a child with a particular disease. To help them in 2013, the American company JScreen was created, which conducts genetic tests for the carriage of 104 genetic diseases, the most common in the Jewish environment.

On the JScreen website, 19 violations are highlighted in a separate list and described in some detail. These include, among others, ovarian cancer, Tay-Sachs disease (amaurotic idiocy, it is believed that one of 30 Ashkenazi Jews carries its gene), Bloom syndrome (increased predisposition to diabetes, lung diseases and oncology), spinal amyotrophy (SMA, chronic and progressive muscle weakness without cognitive impairment), familial dysautonomia (damage to various body systems), as well as Kenewen's disease (impaired motor skills and mental retardation). The remaining 85 diseases are a simple enumeration.

The bulk of American Jews are from Eastern and Central Europe, and therefore the descriptions on the JScreen website focus on them. But the test panel itself is designed taking into account the most common diseases in all three Jewish groups – Ashkenazim, Sephardim and Mizrahim. Depending on the cluster, the degree of prevalence of a particular disease may be different – for example, among Ashkenazim, the probability of becoming a carrier of SMA is 1 to 41, and among Egyptian Jews – already 1 to 10. "If both parents have a common "sick" gene, then each of the children is 25% likely to be born with the corresponding disease," warns JScreen, recalling the laws of recessive inheritance.

The JScreen program was opened on the basis of the private Emory Research University in Atlanta, Georgia, but its representatives travel all over the country and offer the younger generation to test their genes. Passing such a test is literally a trivial matter. It is enough just to collect a little saliva in a cone, send it to geneticists, and in 4-5 weeks the results with explanations will be ready. The cost of the study is rather big – $ 1000, but it will be done for $99 under insurance. But some do not need to pay that much – more than 1,000 people have already passed free tests as part of a joint action of Yeshiva University in New York and JScreen, as well as 50 students of the University of Georgia.

The JScreen panel is hardly narrow, but there, for example, there is no test for genetic predisposition to the development of Parkinson's disease, although it has long been on the list of the most common among Ashkenazim. On the website of the famous Michael J. Fox Foundation for the Study of Parkinson's Disease, it is noted that one of the most common causes of the development of this disease are mutations of the LRRK2 gene. One of these mutations, G2019S, is particularly common among Ashkenazi Jews and North African Berbers - in 14% and 30-40% of patients, respectively. However, not every one of them can develop the disease and begin to progress – studies of carriers of altered LRRK2 among representatives of the Jewish world have shown that only 25-35% of them develop the corresponding symptoms.

There is also no other progressive disease in the list – torsion dystonia, which leads to compulsive contractions of the muscles of the trunk and limbs, although this disease is most often found among the descendants of Central European Jews. The transmission of this gene occurs more often in an autosomal dominant type, that is, only one parent is usually enough to inherit a "broken" gene. Carriers of torsion dystonia in the Ashkenazi cluster occur with a frequency of 1 in 9,000 people, and the disease itself develops in 1 out of 15,000 representatives of this subethnic group. To understand the scale of the spread, you can take albinism – in the world it also occurs on average in 1 case out of 15,000.

But genetic changes are not always a bad thing. Quite a large number of Jews have another mutation, quite useful, which is also transmitted from parents to children. About 20% of people of Jewish origin have an altered ADH1B gene (or, as it was called earlier, ADH2*2), which increases resistance to alcoholism. It is also not taken into account in the JScreen panel, but this is understandable – such a "breakdown" is more a blessing than a problem. This mutation provokes the production of a more active form of the enzyme, which accelerates the first stage of alcohol metabolism. The altered gene increases the level of acetaldehyde, which is a byproduct of alcohol decomposition and causes headaches and nausea in large quantities. Those who have this gene, it is very unpleasant to drink alcohol, and often they drink extremely rarely.

Even if you have this gene, you do not need to abuse alcohol, otherwise the magic protection can be reduced to zero. Scientists have found that the modified ADH1B works most effectively among Sephardim, in whose culture there is no place for alcohol at all, and worse among Jews who repatriated from Russia, where drunken gatherings are part of the culture.

Portal "Eternal youth" http://vechnayamolodost.ru  20.04.2016