Families with several CF people

Question

Hello
Are there families with several people with cystic fibrosis ?
Thank you

Answer

Hello,
Yes, there are "direct" families with several CF children and "extended" families with several CF cousins.
Cystic fibrosis is a genetic disease transmitted in an recessive autosomal way. In practice, this means that both parents of a sick child are healthy carriers of a CF gene mutation, say they are not sick but can transmit the disease to their offspring, boys as well as girls.
For these couples "at risk", the probability of having a CF child is statistically 1 in 4 at each pregnancy. This ¼ value representing the statistical risk is just applicable in large populations involving all children of many couples at risk.
Indeed, for a given couple at risk, the chance may vary from none (even if several or many children) to one or several sick children.
A " Genealogy and CF " database was set up for the CF patients followed up since the 60s by the Centre of Perharidy, Roscoff, France. The creation and analysis of this database was the object of the PhD thesis of Ms Nadine Pellen.
In 2014, it included 1,289 patients belonging to 1,116 families. The number of CF siblings in the same family was:
• 6: one family;
• 4: 3 families;
• 3: 22 families;
• 2: 117 families;
• 1: 973 families.
The database built by ascending genealogy studies do not take into account the relationship between cousins: it explains we cannot extract the number of "extended" families with several CF cousins or children.
The number of couples with several sick children (and extended families with several CF cousins or siblings) is however decreasing for several reasons:
• the reducing number of children per couple;
• the implementation of the systematic newborn screening with identification of couples at-risk and possibility to offer them (and their relatives: sisters, brothers, cousins) a genetic counseling;
• the possibility of antenatal diagnosis in early pregnancy for couples at risk and, in case of CF fetus, a possible recourse to a pregnancy termination;
• the choice of adoption for at-risk couples who desire children but not a pregnancy termination in case of CF of the fetus.
If you are related to a CF patient, it is important to know that you can benefit from genetic counseling and possibly genetic testing. To be guided, you can contact a CF Center near your home by clicking on the following link :
www.vaincrelamuco.org/ewb_pages/c/centres-reference.php [French Website]
Hope that answers your question.
Gilles RAULT, MD
Reference Centre Nantes- Roscoff
with the kind support of:
Nadine PELLEN, PhD

14.05.2014