Trisomy 18: Edwards' Syndrome

On September 10^th, Donnie Heaton turned 21. However, he is not like other 21-year-olds because he only weighs 55 pounds, or 25 kg. This is, according to a story from the DNA Science Blog, because he has genetic condition known as trisomy 18, or Edwards’ syndrome, which means that each of his cells has an extra chromosome 18. This happened because of a genetic mutation during mitosis, when chromosomes accidentally got misplaced, therefore one of the sex sells had an extra chromosome 18, which was then passed on to Donnie (see  fig.1).

Fig.1: Donnie Heaton, the oldest person alive with trisomy 18, and his mother.

 According to a page on NHS, ¾ of babies with Edwards’ syndrome are miscarried or stillborn, and if the baby survives beyond 1 year, then it will have a developmental disability, just like Donnie. The extra chromosome disrupts the normal course of development, and the baby grows very slowly in the womb, so most are born with a very low birth weight.

Some symptoms of Edwards’ syndrome include heart and kidney problems, poor growth, breathing problems, bone issues such as curved spine, frequent infections, and severe learning disabilities. The physical appearance of a person with trisomy 18 is slightly different from ordinary people. They often have a small, abnormally shaped head, long fingers that are fisted and overlap, low-set ears, and rocker-bottom feet (feet with a rounded base).

This condition is on the more serious side. Most do not even survive until childbirth. Only 5-10% survive beyond one year. However, those with partial forms of the disorder usually live until adulthood. An interesting fact is that Edwards’ syndrome affects 3 times more girls than boys. The disorder affects around 1 in 3000-5000 live births, and the chance of having a child with Edwards’ syndrome increases with the mother’s age. Sadly, there is no cure for the disorder, and the symptoms are very difficult to manage.

 Donnie is one of the oldest with the disorder, and his mother was 42 when she had him. She says she doesn’t believe in abortion, so she didn’t have an amniocentesis (a screening of the fetus to find any abnormalities), therefore she didn’t know that Donnie was going to have Edwards’ syndrome. The doctor in the delivery room knew right away what was wrong, and he said, “take him home and love him and he’ll die in your arms”. The doctor was wrong. He didn’t die; Donnie turned out to be a lot healthier than the doctors said. However, he is very low-functioning (see fig. 2).

Fig. 2: Donnie at his special needs school with his mother and other special needs people.

 Donnie had pneumonia 3 times in 1 year. He has fevers, heart problems, urinary infections, and he breaks his fragile bones. He doesn’t walk or talk. He only weighs 25 kg, and he won’t grow any more. But somehow, his mother says, he keeps going. He is a person. He reacts. He knows things. He recognizes people, and he shows emotion, just like any other human being. He is a rare one though, and he is believed to be the oldest person in the world with trisomy 18.

According to his mom, he likes watching football, and he likes the different colored lights and the sound of the clapping. He picks up on all the excitement. She says, “there’s a light inside those eyes, I can see it. Donnie amazes me”.