In this article we will discuss about some common misconceptions and misinterpretations about genetic disorders.
It is important to recognize that there are many potential misconceptions concerning genetic disorders and risks that need to be identified and rectified to ensure that families understand the information they are given and can use it appropriately.
Some common misconceptions and misinterpretations are as follows:
1. All disorders or malformations present at birth have a genetic basis and are inherited.
2. Chromosomal disorders are always inherited.
3. All genetic disorders and their carrier state can be detected by chromosome analysis.
4. Absence of other affected members indicates that a disorder is not genetic/inherited.
5. A pattern observed in a family will be maintained, i.e., only females affected, even though the disorder is autosomal dominant.
6. Sex-linked inheritance must apply if only males or females are affected in the family.
7. A 1 in 4 recurrence risk means that only 1 of 4 children will be affected and if the first child is affected, the next three will be unaffected.
8. A 1 in 20 risk for recurrence is interpreted as a 1 in 20 chance of a healthy child.
9. Confusion of odds, fractions, and percentage risks.
10. Confusion of carrier risk with risk of an affected child.
11. Physical or emotional upsets during pregnancy cause malformations.
12. Scientific explanations may be acknowledged but overruled by cultural beliefs.
It is important to remember that perception of risk may vary greatly. A 5% risk may be perceived as low by one individual, but unacceptably high by another. In general, perception of risk is affected by severity of the disorder.
A high risk of a mild or treatable disorder may be accepted, whereas a low risk of a severe disorder has greater impact on reproductive decisions. It is often helpful to put risks into context by comparing them with the general population risk for the particular disorder, or the overall risk of 2% that any pregnancy might result in the birth of a child with a congenital or genetic abnormality.