Trisomy 18 (Edwards Syndrome)

The triple occurrence of chromosome 18 in the cells is referred to as trisomy 18, or Edwards syndrome after the person that first described it. It is the second most common chromosomal disorder after trisomy 21and about one in 10,000 to one in 3,000 children are affected by it. The children are often extremely underweight at birth and show typical physical characteristics, the head being altogether too small and the back of the head extremely prominent. The mouth-chin area is small and the eyelid folds are narrow. Anomalies of the eyes and cleft lip/cleft palette are also common. A characteristic feature is overlying fingers, whereby the index finger is folded over the 3rd and 4th fingers. Sometimes the bone on the thumb side of the hand is missing, sometimes the entire thumb, and the feet are also malformed.Of the inner organs, in particular the cardiac septum (VSD) is affected, as well as the kidneys, the digestive tract and the brain. Most children do not survive their first year of life.