{{Genotype
|allele1=G
|allele2=T
|iid=4000314
|magnitude=3
|repute=Bad
|summary=Cystic Fibrosis carrier
}}
This mutation is also known as 621+1G>T and 489+1G>T.  It is a Class I splicing mutation, indicating it results in a premature termination codon.  If a CF carrier has a child with another CF carrier, then the child has a 25% chance of having Cystic Fibrosis.

In SNPedia and the rest of the world (i.e. outside of the company 23andMe), this SNP is known as [[rs78756941]].