The CFTR gene is located on the long arm of chromosome 7. As of this writing, genomic advances have led to the identification of 1,965 CFTR mutations, though the number continues to rise. There is evidence that 127 mutations sufficiently impair CFTR function to produce CF symptoms. Of the remaining mutations, 225 are known to produce no symptoms, and the others are of unknown clinical significance. A project called the Clinical and Functional Translation of CFTR is dedicated to documenting all CFTR mutations and associated clinical presentations.