Ubiquitin: do y u think EVERY intellectually disabled person fits neatly into Trisomy 21, Fragile X, Prader willi etc?
If there are normal facial features, it is probably NOT genetic retardation. There are other causes of retardation besides genetic including: prenatal exposure to alcohol, drugs or other toxins,birth trauma (oxygen deprivation) lead poisoning, mercury poisoning, malnutrition, encephalopathy, brain injury, etc.