Down syndrome is the most common intellectual disability caused by genetic problems,and its physical characteristics include grow impairment, loss of muscle tone, and distinctive facial features. Complications include thyroid disease, otolaryngological disease, ophthalmological disease. Some of which may require medical treatment, such as congenital heart disease, which may also result in organ damage.
Many of these children attend local schools or special needs schools with support classes. They may be active in sports, the arts, and many other areas.

Edwards syndrome is may be caused by developmental failure in utero, most often resulting in miscarriages or stillbirths. Most of those born alive have multiple congenital defects in the brain, heart, and other organs, and many die before the age of one, while those who survive have problems with intellectual disability and developmental disabilities. Their physical characteristics include growth impairment from the fetal stage, and breathing and eating problems. Complications include heart disease (90%), gastrointestinal malformations, cleft lip and palate, and joint contractures.

Most children with Patau Syndrome will have congenital defects in the brain and other organs. Most of the children with this condition are miscarried or stillborn, and 80% of those who survive at birth die before the age of one month. 10% of the children with this condition die within a year of birth.
Their physical characteristics include growth impairment ,and breathing and eating problems/disorders.
Complications include cleft lip and palate, polydactyly, eye disease, heart disease (80%), and holoprosencephaly, which are congenital defects in the brain and organs.