CFTR and cystic fibrosis: It is considered to be a pathogenic variant linked to CBAVD or other atypical symptoms of CF.46 Moreover, the 5T variant in combination with longer (TG)12 or (TG)13 repeats probably results in an increased disease risk compared with that of 5T itself.47 In vitro studies have shown that 5T/(TG)12 results in shorter transcript variants, leading to deficient CFTR protein function and consequently inducing abnormal fluid secretion and electrolytes.48 However, owing to the limited data extracted from the original studies, we did not conduct a meta-analysis of 5T/(TG)12_13 frequency here.