Edwards Syndrome

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Edwards syndrome is a genetic disorder, in which a person has a third copy of material from chromosome 18, instead of the usual two copies. It is three times more common in girls than boys. The syndrome is caused by the presence of extra material from chromosome 18, which interferes with the normal development.

It is often referred to by another name, i.e. trisomy 18.

Symptoms of Edwards syndrome

The symptoms of Edwards syndrome may differ from one affected individual to another. Some of the signs and symptoms of Edwards syndrome are as follows:

Underdeveloped fingernails
Undescended testicles
Unusual shape of the chest
Feet with a rounded bottom
Low birth weight
Clenched hands
Under developed or missing thumbs
Crossed legs
Webbing of second and third toe
Upturned nose
Widely placed small eyes with narrow eyelid folds
Drooping of upper eye lids
Low-set ears
Mental deficiency
Small head
Small jaw
Cleft in iris
Umbilical hernia
Diastasis recti
Structural malfunctions of heart, brain, genitals, kidneys, and the digestive tract, may cause problems in breathing, feeding etc.
Delay in growth and development
Infections in lungs and in urinary system

Causes of Edwards syndrome

Edwards syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on the 18th chromosome, either in whole or in part. The additional chromosome usually occurs before conception. The effects of the extra copy vary greatly, depending on the extent of the extra copy, genetic history, and chance.
A healthy egg or sperm cell contains individual chromosomes; each of which contributes to the 23 pairs of chromosomes needed to form a normal cell with 46 chromosomes. Edwards syndrome results in an extra chromosome, making the number 24 rather than 23. Fertilization of eggs or insemination by sperm that contain an extra chromosome results in trisomy, or three copies of a chromosome rather than two.
A small percentage of Edwards syndrome cases occur when only some of the body’s cells have an extra copy of chromosome 18. Such cases are called as mosaic Edwards’ syndrome. Very rarely, a piece of chromosome 18 becomes attached to another chromosome (translocated) before or after conception. Affected individuals have two copies of chromosome 18 plus extra material from chromosome 18, attached to another chromosome. With a translocation, a person has a partial trisomy for chromosome 18, and the abnormalities are often less severe than for the typical Edwards syndrome.
Edwards syndrome is not an inherited disorder, it happens at random during the egg or sperm formation, which is known as nondisjuction, and is responsible for the extra chromosome. The reason for causing abnormalities by the extra material is unknown. However the experts believe that it interferes in the interaction of various genes and cause impairments.
One child in 6000 births is affected by Edwards syndrome. 80% of children with this syndrome belonged to female segment. Majority of the syndrome affected children die before birth. People with all types of cultural background get affected by this syndrome. The risk of Edwards syndrome increases with the increase in the maternal age.