Down syndrome is a hereditary disease discovered in 1866 by. Dr. John Langdon Down. Patients with down syndrome demonstrate certain degree of learning disabilities or physical characteristics and health problems, such as congenital heart disease of varying severity. Some children with Down syndrome can live a normal life with special care and education.

Down syndrome is caused by an extra chromosome on chromosome 21. Most cases of Down syndrome occur by chance and lack of evidence indicates that down syndrome is related to the mother's lifestyle before or during pregnancy. 

Approximately 1 in 700 newborn babies has Down syndrome, and the chance increases with the age of the pregnant woman correspondingly. Down syndrome is one of the conditions that can be detected prenatally.

Physical characteristics

People with Down syndrome have unique physical characteristics. 

Characteristics of people with Down syndrome include:

• Eyes: The distance between their eyes is wide and the outer side of the eye is slanted upward.
• Nose: The bridge of the nose is low and flat.
• Ears: The outer ear is small.
• Mouth: Larger tongue.
• Head: Head circumference is less than normal with shorter anterior and posterior diameters of the head and flat occipital.
• Neck: Short neck, loose skin.
• Figure: Short stature, the development of bone is often lags compared with normal people in same age and delayed or misplaced development of teeth. 

Health Problems

The following health problems are more common among people with Down syndrome: 

• Congenital heart disease: About 40-60% of infants with Down syndrome are born with heart problems that may require surgery.
• Immune system problems: They have inferior immune function and are prone to infection.
• Thyroid function problems: Hypothyroidism may occur which affects mental and physical health.
• Vision and hearing problems: such as myopia, strabismus and hearing loss.
• Respiratory problems: such as sleep apnea.
• Blood disorders: Risk of acute leukemia is higher, despite the fact that it is still rare.
• Muscle and bone problems: Inferior muscle tone may lead to slow development of motor function.
• Mental health problems: such as depression and anxiety, and a certain percentage of autism.

Above-mentioned characteristics and health problems of Down syndrome are caused by an extra third chromosome on chromosome 21. Although these physical characteristics and health problems are common in people with Down syndrome, each person's circumstance is unique. In addition, people with Down syndrome have their own personalities and talents, and they can develop their potential with appropriate support and education. It is important that society provides an inclusive and supportive environment where people with Down syndrome can live fulfilling and meaningful lives.