Clinical Phenotypes and Genotypic Spectrum of Cystic Fibrosis in Chinese Children

Objectives To characterize the clinical phenotypes and genotypic spectrum of cystic fibrosis (CF) in Chinese children. Study design We recruited and characterized the phenotypes of 21 Chinese children with CF. All 27 exons and their flanking sequences of the CF transmembrane conductance regulator gene were amplified and sequenced to define the genotypes. Results Bronchiectasis (95.2%) and sinusitis (76.2%) were the most common clinical presentations among our patients. By contrast, pancreatic insufficiency was rare (14.3%). The predominant organism found in the airways was Pseudomonas aeruginosa (66.7%). There were obvious reductions of forced expiratory volume in the first second (mean +/- SD: 71.8% +/- 17.2% predicted) and forced expiratory flows at 75% of exhaled vital capacity (33.7% +/- 20.4% predicted) in children with CF. Overall, we identified 22 different mutations, including 12 missense, 5 nonsense, 2 frameshift, 1 in-frame insertion, 1 splice site, and 1 30untranslated region mutation. Of these, 7 were novel observations (W216X[780G -> A], 1092insA, Q359X, D567Y, 2623-126T -> C, 3439delA and 4575+110C -> G), and the most common types were L88X and I556V. One de novo mutation (1092insA) was also revealed. Except for N1303K and R334W, none of them were present in the common Caucasian CF transmembrane conductance regulator mutation-screening panels. Conclusions There was a 5.7-year delay between the first clinical presentation and the eventual CF diagnosis, suggesting that CF may be underdiagnosed in China. The clinical phenotypes and genotypic spectrum are different from that observed in Caucasians.