Which are the causes of Edwards syndrome?

Causes of Edwards Syndrome

Edwards syndrome, also known as trisomy 18, is a genetic disorder caused by the presence of an extra copy of chromosome 18 in the cells of an individual. This additional genetic material disrupts the normal development and functioning of the body, leading to various physical and intellectual disabilities. The exact cause of Edwards syndrome is not fully understood, but it is believed to occur randomly during the formation of reproductive cells or early embryonic development.

Chromosomal Abnormality:

The primary cause of Edwards syndrome is a chromosomal abnormality known as trisomy 18. Normally, each cell in the human body contains 23 pairs of chromosomes, totaling 46 chromosomes. However, individuals with Edwards syndrome have an extra copy of chromosome 18, resulting in a total of 47 chromosomes. This additional genetic material disrupts the normal genetic balance and leads to the characteristic features and health problems associated with the syndrome.

Non-Disjunction:

The most common cause of trisomy 18 is a process called non-disjunction. Non-disjunction occurs when chromosomes fail to separate properly during the formation of reproductive cells (eggs and sperm) or during early cell division in the embryo. As a result, one of the resulting cells ends up with an extra copy of chromosome 18, leading to trisomy 18 in the affected individual.

Advanced Maternal Age:

Advanced maternal age is a significant risk factor for the occurrence of Edwards syndrome. The likelihood of having a child with trisomy 18 increases as the mother's age advances, particularly after the age of 35. The exact reason behind this association is not fully understood, but it is believed that the aging process of the eggs may contribute to an increased risk of chromosomal abnormalities, including trisomy 18.

Parental Translocation:

In rare cases, Edwards syndrome can be caused by a parental translocation. Translocation occurs when a piece of one chromosome breaks off and attaches to another chromosome. If a parent carries a balanced translocation involving chromosome 18, there is a risk of passing on an unbalanced translocation to their offspring. This unbalanced translocation can result in trisomy 18 in the child.

Environmental Factors:

While the primary cause of Edwards syndrome is related to chromosomal abnormalities, there is no evidence to suggest that environmental factors or parental behavior contribute to its occurrence. The condition is not caused by anything the parents did or did not do during pregnancy.

Conclusion:

Edwards syndrome, or trisomy 18, is a genetic disorder caused by the presence of an extra copy of chromosome 18. The most common cause is non-disjunction, where chromosomes fail to separate properly during reproductive cell formation or early embryonic development. Advanced maternal age is a significant risk factor, and in rare cases, parental translocation can also contribute to the occurrence of trisomy 18. It is important to note that environmental factors or parental behavior do not play a role in causing Edwards syndrome.