Mild cystic fibrosis and normal or borderline sweat test in patients with the 3849 + 10 kb C-->T mutation

Lancet. 1993 Jul 3;342(8862):25-6. doi: 10.1016/0140-6736(93)91885-p.


Different mutations in the cystic fibrosis (CF) gene appear to contribute to heterogeneity of the CF phenotype. We investigated 15 patients with CF who have the 3849 + 10 kb C-->T mutation. All were Ashkenazi Jews. Their clinical features were compared with those of CF patients with the delta F508/delta F508, W1282X/W1282X, W1282X/delta F508 mutations, which are known to be associated with a severe disease. Patients with the 3849 + 10 kb mutation were older, had been diagnosed as having CF at a more advanced age, and were in a better nutritional state. Sweat chloride values were normal (below 60 mmol/L) in 5 3849 + 10 kb patients (33%). 4 of these patients and 6 others (total 66%) had normal pancreatic function. However, age-adjusted pulmonary function did not differ between the two groups. None of the patients with 3849 + 10 kb C-->T had had meconium ileus or had liver disease or diabetes mellitus. We conclude that this mutation is associated with a mild type of CF.

MeSH terms

  • Age Factors
  • Child
  • Chlorides / analysis*
  • Cystic Fibrosis / genetics*
  • Female
  • Humans
  • Male
  • Phenotype
  • Point Mutation*
  • Sweat / chemistry*


  • Chlorides