A group of researchers belonging to the Department of Molecular Genetics of Cruces Hospital (Bilbao) have discovered that the duplication of the RPS6KA3 gene, included in the X chromosome, causes a mild intellectual disability to the children of carrier women who do not have symptoms.

The research, published this Wednesday in the magazine Pediatricsis important because although there are numerous studies on the genetic factors involved in severe intellectual disability, the genetic causes of mild intellectual disability are barely known, as explained by the research coordinator, Dr. Isabel Tejada, who adds that the results of the study will serve to improve the quality of life of the patients, to whom it will be possible to administer a more appropriate treatment, in addition to preventing other cases in the same family and thus saving healthcare expenses.

The results will serve to improve the quality of life of the patients, to whom a more appropriate treatment can be administered, in addition to preventing other cases in the same family and saving healthcare expenses.

The scientists investigated the case of a child who suffered a psychomotor delay since he was one year old, who lacked facial dysmorphism or other associated anomalies, and who was referred to the genetics laboratory for study. Two uncles of the child, brothers of their mother, presented psychomotor retardation in their childhood and did not finish primary school, although they live independently.

The patient underwent "a karyotype or chromosomal study and a molecular study of the X fragile syndrome", but as these tests did not register a positive, and due to the existence of family background, the experts decided to continue with the investigation.

Development of the study

They used a technique called MLPA (Multiplex ligation-dependent probe amplification) that contains some portions of the genome that needed to be analyzed, taking into account the three known family patients that were associated through the maternal route. The geneticist notes that they then observed a duplication of a very small region, not described, and that it contained seven genes of which only one, RPS6KA3, is related to mental retardation.

However, the alterations of this gene cause another type of syndrome that they did not find in the studied patient, reason why the researchers point out that it is a new entity and that, as in the case of other syndromes, the fact that One or several duplicated genes appear as a consequence of a pathological effect opposite or different from point mutations, and that is the over-expression of one or several proteins, and not their lack, which causes the pathology.

To conclude, the scientists checked the hypotheses obtained in the research with other complementary tests.


How much do you know about intellectual disabilities? | Matthew Williams | TEDxVancouver (November 2019).