Terminology

Missense: A base pair change in DNA sequence that results in the substitution of one amino acid for another.

Nonsense: A base pair change in DNA sequence that causes translation to stop.

Frameshift: insertion or deletion of base(s) in DNA sequence that results in shift in the reading frame during translation.

In frame in/del: insertion or deletion of bases in DNA sequence that does not result in shift in the reading frame during translation.

Large in/del: insertion or deletion of large number of bases in DNA sequence.

Sequence Variation: sometimes designated as "polymorphism", indicating that it is "non-disease causing". According to the general definition in human genetics, a "polymorphism" has to reach an allelic frequency of 1%. In addition, when a sequence variation is found in one single individual, it is not possible to determine if it is "non-disease causing".

Splicing: a mutation that causes mRNA splicing defect.

Promoter: a mutation that happens at promoter region.

Frequently Asked Questions

1. Where can a find the sequence for the CFTR gene?
The sequence for the CFTR gene can be found here.

2. How many mutations are currently listed on this web site?
There are currently 2121 mutations listed on this web site.

3. Please explain the nucleotide change for mutation p.F508del and mutation p.I507del?
The nucleotide change of p.F508del - "deletion of three bp between nucleotides 1519 to 1524" means any 3 consecutive nucleotides in this range of 4 nucleotides: either T(1520)C(1521)T(1522) or C(1521)T(1522)T(1523). Both 3 bp deletions lead to the same DNA sequence: A(1519)TTT(1524)G(1525).

The p.I507del is much easier to understand because of the two consecutive isoleucine codons (ATC) between nucleotides 1515 and 1522 e.g. A(1516)T(1517)C(1518) - A(1519)T(1520)C(1521). Deletion of any of 4 consecutive 3b in this range (1516-1521) would produce the same sequence.