Registry Study on Cystic Fibrosis in Chinese Children

Inclusion Criteria: * Age 0\~18 years old * Any organ system symptoms consistent with CF, such as chronic sinopulmonary disease, gastrointestinal and nutritional abnormalities, obstructive azoospermia or having siblings with CF * CFTR dysfunction indicated by elevated sweat chloride levels ≥60 mmol/L twice, or one sweat chloride levels ≥40 mmol/L plus presence of two pathogenic CFTR mutations on different alleles * Probable CF patients with sweat chloride levels among 40\~59 mmol/L plus with presence of 0-1 pathogenic CFTR mutation * Consent to provide the related clinical specimen to the certain hospital * The guardians of the patients fully understand the purpose of the study, volunteer their children to participate in this study and sign informed consent. Exclusion Criteria: * Subject will be excluded if she or he has one of the following: * It is unable to provide complete medical records or the current condition can not accept the diagnosis process. * She or he does not agree to participate in the test.