Genetic counseling of parents of children with eye diseases
François, J.
Journal de Genetique Humaine 28(4): 105-122
1980
ISSN/ISBN: 0021-7743 PMID: 7205195 Document Number: 162879
What is the empirical risk for children to be born with a disease or a malformation? In healthy families, the parents being normal, the probability is 2 to 4% and when the parents are first cousins, although healthy, it is 5%. Of course, the risk is greater in affected families. When the mother or the father is affected and when there is no consanguinity, the risk is 20%, but when the parents are first cousins, it is 32,5%. When the two parents are affected, it is 100%. When the parents are normal, but when already one child is affected, the risk for the other children is 25%. When the mother or the father is affected and when there is already one child affected, the risk for the other children is 50%. When a grand parent is affected, the risk for the grand children is 10%. When an aunt or an uncle is affected, the risk for the nephews and nieces is 7%. In the case of genetic counseling, the parents must understand that no physician can guarantee that a child will be normal. On the other side, they must understand that the mendelian risks are the same for each pregnancy. Finally, they must know that at each birth there is a risk of 2 to 4% of having a major congenital anomaly. On the human and psychological point of view, the physician must convince the parents that they are not responsible and that, if a woman may be a gene carrier, the husband may also carry pathological genes, as each individual carries 2 to 10 pathological recessive genes. Finally, it is not the geneticist who has to impose a procreative decision. Only the parents have to decide if they want or do not want other children.