Trisomy 18: What is it, Causes, Symptoms and Prognosis

, is a rare genetic disease characterized by the presence, in the cells of the affected individual, of a third chromosome 18.

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Trisomy 18 is a very serious condition incompatible with life: most of those affected, in fact, die before birth or are stillborn.
According to the most reliable research, it seems that trisomy 18 is due to a "genetic aberration that takes place before conception and that concerns a sex cell of one of the parents or shortly after conception.
Generally, for the prenatal diagnosis of trisomy 18, prenatal ultrasound, bi-test, tri-test, skeletal radiography, echocardiography and amniocentesis are needed.
Unfortunately, being the result of an unrecoverable genetic error, trisomy 18 is an incurable condition, even when detected at an early stage of fetal development.

of Edwards, is a serious genetic disease, characterized by the abnormal presence, in the cells of the affected individual, of a third chromosome 18.
Trisomy 18, therefore, is a genetic disease that alters the total number of chromosomes present in the cells of an individual: due to the presence of a third copy of chromosome 18, in fact, the cells of a patient with Edwards syndrome contain 47 chromosomes, instead of the normal 46.
Trisomy 18 is always incompatible with a normal life: most carriers die in prenatal age or within the first year of age.

In genetics, the abnormal chromosomes that are added to the two canonicals are called supernumerary chromosomes.