Screening test in pancreatic sufficient people

Question

Good evening,
How can mild cystic fibrosis forms be detected through the neonatal test even though those patients do not have pancreatic insufficiency? I read in an article that patients with pancreatic sufficiency are not detected in the Guthrie test but several times I read the opposite. Has the neonatal test been improved over time to detect these milder forms? Has the test changed? How many false negatives were detected on symptoms in 2015? What are the most often mutations missed by the neonatal screening?
Thanks in advance

Answer

Hello,

Mild forms of cystic fibrosis can be detected by the newborn screening test even if the children do not have exocrine pancreatic insufficiency. The obstruction of the pancreatic ducts by thick, sticky mucus can be incomplete without consequence on the secretion of pancreatic enzymes in the digestive tract but be sufficient to cause lesions of the pancreas with an abnormal passage of this enzyme (IRT) to the blood.

As stated in a previous response posted on the site of ECORN-CF,

ecorn-cf.eu/index.php?id=65&L=8&tx_expertadvice_pi1%5Bshowitem%5D=3786&tx_expertadvice_pi1%5Bsearch%5D=


the last false negative survey of CF newborn screening led by the French Association for Testing and Prevention of Child’s Handicaps (AFDPHE) found exactly the same proportion (48%) of false negatives in both pancreatic sufficient children and pancreatic insufficient children.

The proportions of false negatives are identical in the 2 groups, however, pancreatic sufficiency is about 5 times less common than pancreatic insufficiency in infants with cystic fibrosis it can be concluded that the IRT-DNA testing is 5 times less sensitive in cases of pancreatic sufficiency.

Hop this answer can help.
Best wishes
Gilles RAULT, MD, Roscoff CF Center

18.04.2016