A survey of families known to have history of mental impairment carried out by scientists revealed a group of genes that cause learning disabilities in boys. Nine genes were linked to poor brain development in young men, after the genetic makeup of 208 families that have at least two related males affected by learning disorders, were being anaylsed. The findings added to 70 other genes on the X chromosome that have already been linked to abnormal brain development in boys.
It was found that all the abnormal genes were on the X chromosome that boys inherited from their mothers which suggested that the genes were sex linked. Learning disabilities resulted from poor brain developement is less prevalent in female as the faulty gene on one X chromosome is counteracted the other healthy copy. In the study, male participants with learning disabilities showed no other signs of developmental problems. The affected male can never pass the genes to their son but can only transmit them to their daughters via the X chromosome. The daughters are unlikely to be affected but will be carriers and are at risk passing the faulty genes to their children.
Yet, there are no obvious cure for these conditions. Nevertheless, the findings could benefit to the development of screening programmes for couples that are at risk of transmitting faulty genes to their children.
