What are Trisomy Disorders?

A Trisomy disorder is a chromosomal disorder, which is characterized by an additional chromosome. Humans regularly have 23 pairs of chromosomes. In case of a disorder, an individual may have 47 instead of 46 chromosomes. A chromosome disorder occurs when there is an alteration in the number of genetic structure of chromosomes. Kids affected by trisomy disorder commonly have a wide range of birth defects, such as intellectual disabilities and delayed development. The common forms of trisomy include Edward syndrome, Down syndrome and Patau syndrome.
The cause of this disorder is still unknown and the biggest risk factor is the mother's age. Those women who decide to give birth between their 30s and 40s are more presupposed to having children with trisomy, compared to younger women.

Trisomy 21- Down Syndrome
1 in 300 pregnancies is affected by Down syndrome. It's known as Trisomy 21 because the individual has 3 copies of chromosome 21 instead of 2.
Some of the main characteristics of Down syndrome are:

  • Flattened face
  • Exaggerated fold of skin on the inside of the eye
  • Flat ears set low on the head
  • Outwardly slanted eyes
  • Small teeth
  • Relatively short arms and legs

Trisomy 18 – Edward Syndrome
Edward syndrome is not as common as Down syndrome is. It affects about 1 in 1000 pregnancies. It's called Trisomy 18 because the person has 3 copies of chromosome 18 instead of 2.
The main signs of Edward syndrome include:

  • Cleft lip or cleft palate
  • Small size of skull
  • Defects of the kidneys, heart, ureters, diaphragm and lungs
  • Malformations on the sex organs
  • Neural tube effect, when the spinal cord, blood vessels and meninges protrude through a gap in the vertebrae.
  • Malformations of the feet and hands

Trisomy 13 – Patau syndrome
Affecting about 1 in 3,000 pregnancies, Patau syndrome is also known as Trisomy 13. Having this disorder an individual has 3 copies of chromosomes 13 instead of 2.
Among the main signs of Patau syndrome there are:

  • An abnormal opening in the skull
  • Small skull
  • Cleft palate or cleft lip
  • Structural defects of the eyes
  • Additional fingers or toes
  • Congenital heart disorders
  • Malformations of the brain
  • Malformations of the sex organs

To get help, you can consider consultation with your doctor or pediatrician.