Genetic intellectual disability can be caused by a number of factors. Some disabilities can be diagnosed, like Down syndrome, Fragile X syndrome, Rhett’s syndrome and others, but many cannot. They can be caused by something as dramatic as an entire extra copy of a chromosome, like Down syndrome (trisomy 21), or something as small as a microdeletion, or a small missing part of a chromosome, like cri-du-chat syndrome, or 5p- syndrome.
Scientists estimate that there are approximately 1,000 genes that contribute to the functioning of a healthy brain. That leaves great potential for genetic errors at conception that can result in trisomies, monosomies, deletions and translocations and other complex alterations of genetic information contained on the human genome.
The Jerome Lejeune Foundation funds and conducts research into many of these conditions and is constantly investigating tways to improve the lives of those with genetic differences.