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Question

Hello I wanted to know if the Guthrie test detects primarily pulmonary cystic fibrosis? Knowing that this test is sensitive to pancreatic enzymes...
Thank you

Answer

Hello,

The test used in France (and other countries) for routine newborn screening for cystic fibrosis is based on measuring out of a drop of blood a protein of pancreatic origin (the immunoreactive trypsinogen - IRT) and researching mutations in the CF gene, the CFTR gene, using a kit for detecting its 30 most frequent mutations.

This test can detect cystic fibrosis whatever the evolution forms it can take regarding respiratory and digestive symptoms more or less important depending on each case.
In case of positive screening, a high blood level of IRT actually shows an injury of the pancreas constantly present in cystic fibrosis (also called "Cystic Fibrosis of Pancreas") but associated with varying degrees of other organs affect (lungs, liver, gastrointestinal tract ...).
Note that the test name "Guthrie test" actually refers to the screening test of phenylketonuria, the first genetic disease that has been the subject of systematic neonatal screening.

Screening for other genetic diseases was implemented by using the same blood sample taken from the heel of the newborn and deposited on paper blott, so the term “Guthrie test” means in everyday language systematic neonatal screening test for phenylketonuria and other genetic diseases: cystic fibrosis, congenital adrenal hyperplasia, congenital hypothyroidism, sickle cell disease.

Hoping to have answered your question.

Best wishes
Gilles RAULT, MD, Roscoff CF Center

28.09.2015