Disease severity associated with cystic fibrosis mutations deltaF508 and S549R(T-->G).

We compared the clinical severity associated with the two cystic fibrosis (CF) mutations S549R(T-->G) and deltaF508. Clinical and biochemical variables of CF were compared in two age- and sex-matched groups of CF children in the United Arab Emirates (UAE). The clinical severity of mutations S549R(T-->G) and deltaF508 showed comparable patterns, with very low Shwachman scores and high sweat chloride levels. We conclude that patients homozygous for the CF mutations deltaF508 and S549R(T-->G) have a severe clinical presentation and illness and are indistinguishable on clinical grounds.