Is early identification of asymptomatic infants with 'mild' CFTR genotypes clinically useful?

Clinical expression of patients with the D1152H CFTR mutation

BACKGROUND

Discordant results were reported on the clinical expression of subjects bearing the D1152H CFTR mutation, and also for the small number of cases reported so far.

METHODS

A retrospective review of clinical, genetic and biochemical data was performed from individuals homozygous or compound heterozygous for the D1152H mutation followed in 12 Italian cystic fibrosis (CF) centers.

RESULTS

89 subjects carrying at least D1152H on one allele were identified. 7 homozygous patients had very mild clinical expression. Over half of the 74 subjects compound heterozygous for D1152H and a I-II-III class mutation had borderline or pathological sweat test and respiratory or gastrointestinal symptoms; one third had pulmonary bacteria colonization and 10/74 cases had complications (i.e. diabetes, allergic bronchopulmonary aspergillosis, and hemoptysis). However, their clinical expression was less severe as compared to a group of CF patients homozygous for the F508del mutation. Finally, 8 subjects compound heterozygous for D1152H and a IV-V class mutation showed very mild disease.

CONCLUSIONS

The natural history of subjects bearing the D1152H mutation is widely heterogeneous and is influenced by the mutation in trans.