Down syndrome occurs when there is an extra copy of chromosome 21. People with this abnormality is described to be having a physical feature like excess skin at the nape of the neck, flattened nose, single crease in the palm of the hand, small ears, small mouth, upward slanting eyes, wide, short hands with short fingers, white spots on the colored part of the eye. The condition is often associated with some level of mental retardation or learning disabilities. These individuals are also slower to develop social and practical skills, but not all at the same rate. Most of the time language skills may be slow to develop as well as adaptive thinking that helps people function in everyday life.
Turner syndrome is a genetic condition in which a female does not have the usual pair of two X chromosomes. They are described to have an absence or incomplete development at puberty, including sparse pubic hair and small breasts, broad, flat chest shaped like a shield, drooping eyelids, dry eyes, infertility, no periods (absent menstruation), short height and vaginal dryness, can lead to painful intercourse. Although they aren't at high risk for psychological problems, some girls do have problems with body image or self-esteem and some may also be hyperactive. http://kidshealth.org/parent/medical/sexual/turner.html
Klinefelter syndrome is the presence of an extra X chromosome in a male. They have an abnormal body proportions (long legs, short trunk, shoulder equal to hip size), abnormally large breasts (gynecomastia), infertility, sexual problems, less than normal amount of pubic, armpit, and facial hair, small, firm testicles and tall height. It is also said that they have learning difficulties especially in reading and writing as well as to have speech delay or language difficulty that may lead to low self-esteem....