Edward’s syndrome was named after Dr. John Edward
Also called Trisomy 18. It is a form of rare genetic disorder where a portion of a person’s chromosome 18 is duplicated. Children with the syndrome inherit three instead of two, copies of chromosome eighteen.
The majority of people with the syndrome die during the foetal stage. Infants who survive experience serious defects and commonly live for short periods of time. Approximately 5-10% of children with Edward’s syndrome survive beyond their first year of life and these have severe developmental disabilities.
The syndrome occurs in about 1 in 5000 births. Edward’s syndrome affects more boys than girls. Women older than the age of thirty have a greater risk of bearing a child with the syndrome.
Ninety-five percent of children with Edward’s syndrome have what is referred to as, ‘full-trisomies,’ while two-percent are due to translocations where only a portion of an extra chromosome is present. Three-percent of children with Edward’s syndrome have what is referred to as, ‘mosaic tristomies,’ where the extra chromosome is there, but not in every one of the child’s cells.
Most cases of trisomy 18 are not inherited, but occur as random events during the formation of eggs and sperm. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes.
Majority die during the foetal stage.
- Heads are unusually small, while the back of their head is prominent. Their ears are low-set and malformed, and their mouths and jaws are small.
- Hands are often clenched into fists, with their index finger overlapping their other fingers.
- Feet may be clubfeet, as well as toes that may be fused or webbed.
- Many types of congenital heart disease like atrial septic defect, ventricular septal defect, or patent ductus arteriosus may be present.
- Inguinal or umbilical hernia, abnormalities of their urogenital system, malformed kidneys, or undescended testicles in males may be seen.