Edward syndrome is also known as trisomy 18. It is a genetic disorder caused by the presence of all or part of the third copy of chromosome 18. This syndrome affects many parts of the body like children are born small in size and have heart defects. There are other signs also which are associated with this disease like small head, small jaw, severe intellectual disability, clenched fists etc.
The main cause of the disease is problems during the formation of reproductive cells or during early development. Diagnosis of the disease can be done by ultrasound. If the first child is affected with this syndrome, the chance of having the disease in a second child is only 1%.
Edward syndrome occurs around 1 in 5000 live births. Mostly the females are affected with this disease.
The disease is named after John Hilton Edwards, who first described the syndrome in 1960.
Signs and symptoms –
The symptoms of Edward’s syndrome may vary from mild to severe (according to the severity of the disease).
- Kidney malformation – Leads to renal failure and sometimes nephropathies.
- Heart defects at birth – for example, ventricular septal defects, atrial septal defects, patent ductus arteriosus.
- Problems associated with digestive systems like protruding of intestine outside the body, esophageal atresia.
- Intellectual problems that lead to problems associated with the development of the child, physical disabilities, growth deficiency, and feeding problems.
- Difficulty in breathing.
- A physical condition associated with Edward syndrome is the small head (microcephaly), malformed ears, abnormally small jaw, cleft lip and palate, palpebral fissures etc.
- Dropping of upper eyelids known as ptosis.
- Short breastbone.
- Cyst in choroid plexus.
- Underdeveloped thumbs and nails.
- Cardiac and central nervous system anomalies are the most severe symptoms of this syndrome like choroid plexus cyst that is present in the brain, sometimes extra amniotic fluid.
It is caused by a genetic error in which there are three copies of a chromosome instead of three inherited copies from the parents. It is caused by the presence of extra chromosome 18.
The effect of extra chromosome varies greatly. Edward’s syndrome is most commonly seen in females.
As we know there are 23 chromosomes in one reproductive cell, but in this syndrome, there is a numerical problem during meiotic division; that leads to an extra copy of the chromosome.
Trisomy 18(47, XX, +18) is caused by meiotic nondisjunction event and as there is an extra copy of 18 it leads to 24 chromosomes in a gamete.
The doctor may diagnose the trisomy 18 during pregnancy by ultrasound but the most accurate way to diagnose is to take the cells from amniotic fluid and analyze their chromosomes.
The doctor can diagnose the disease after birth also by taking a blood sample to look for chromosomal abnormalities.
There is no cure for this disease.