Rare mutation

Question

Hello,
I am the mother of a little girl of three years, compound heterozygous for mutations F508del and T604i.
I want to know what class of mutations T604i belong?
Here the only information we know. T604i is located in exon 13 (substitution C> T at nucleotide 1943 resulting in the substitution of a threonine with isoleucine at position 604 of the protein.)
Thank you.
E.

Answer

Hello,
Here is the answer of one of the reference laboratories of Genetics in cystic fibrosis:
The mutation 1811C> T, p.Thr604Ile (T604I) is rare, we have observed it only twice in the laboratory, the first time in an adult patient with a mild but complete form of cystic fibrosis (diagnosed at age 25, positive sweat test, moderate pancreatic and lung disease and infertility by absence of vas deferens). No functional studies have been performed.
This is a missense mutation whose pathogenicity is difficult to assess. The results of analysis by bioinformatics tools are not all consistent and should always be interpreted with caution.
It is therefore impossible to tell which "functional" class is the T604I mutation, particularly since a mutation may have polymorphic effects and therefore fall into several classes. This would need to study the messenger RNA of patients.

So you may be requested in future for further studies on your daughter's mutation.

Sincerely,

Dr. Sophie Ravilly with the help of Dr. Emmanuelle Girodon (Creteil)

07.05.2012