3.2 CFTR mutation carrying status
CFTR mutation was not detected in 7 subjects, and 14 CFTRmutations were detected in the remaining 18 subjects. The relationship
between the detected mutations and disease was evaluated according to
the general criteria of United States College of Medical Genetics and
Genomics (ACMG). We found that one sites was Likely Pathogenic, five
were a Variant of Uncertain Significance (VUS), and the rest were graded
as Benign. These sites were searched in ClinVar database, and no CF
pathogenic sites were found. The China population database provided by
Beijing Mygenostics co., Ltd. (included 46648 Han people in the Chinese
mainland area) was selected to query the carrying rate of these
mutations. The MAF of 6 sites was>0.05, which was the SNPs
in the population (Table S1). The whole blood of the parents of the 7
patients with non-SNPs was collected for first-generation verification,
and it was found that these mutations came from one parent (Table S2).
The patients with no CFTR mutation or only one mutation were
tested for Multiplex Ligation-dependent Probe Amplification (MLPA), and
the results were negative. In combination with past medical history,
family history, sweat chloride level test (SCLs, all lower than 60
mmol/L) and preoperative chest X-ray, it can be determined that all the
enrolled children in this study were excluded from the diagnosis of CF.