Detection of CF at a later age

Question

Recently, a mother with CF stated that she did not know she had CF before she was pregnant. I was glad for her, but, on the other hand, I got worried. I have a child with CF (pancreatic symptoms) and other children, that have not been tested (the doctor told me to have them tested for carrying a CF mutation when they get married). They do not look as if they have something. However, a) is it possible to get to the age of 38 without having any symptoms? b) How could an overweight person, over the age of 20, detect possible CF symptoms? c) If CF has not been detected by the age of 20, what about any possible lesions, e.g. would not a 20 year old person have contracted pseudomonas? Thank you!

Answer

Dear friend!
A percentage of CF patients (approximately 10%) are diagnosed after the age of 14 years. Usually, these patients do not suffer from pancreatic insufficiency (i.e. they do not have to take pancreatic enzymes), nor do they present clinical symptoms that could arise any suspicion for CF. The pancreatic function, or pancreatic sufficiency, is a clinical term that denotes the ability of the person to digest fat without having to take pancreatic enzymes. A simple way to test the pancreatic sufficiency is to measure the fecal elastase.
There is correlation between the genotype (i.e. the CF mutations a person carries) and the pancreatic function (Kristidis 1992). Nonetheless, in a small percentage of patients with the same mutations exists the possibility that some will have pancreatic sufficiency, whereas some others will have pancreatic insufficiency (Castellani 2008).
Usually, the mild cases of CF present with nasal polyps, dehydration, pancreatitis, male sterility, with or without other symptoms of the respiratory systems, without pseudomonas infection.
The correct way is to do a sweat test to all the siblings of a child with CF. If the siblings are many, the children that may present suspicious symptoms should be examined first. The genetic testing for the possibility that a sibling of a person with CF is a carrier of a CF mutation should be performed when the sibling reached a reproductive age.

Yours friendly,
Dr. Stavros Doudounakis

12.06.2015