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Abstract Background Although an increasing number of patients with Birt-Hogg-Dubé syndrome (BHD) are being recognized in China, clinical and genetic characteristics are not well-defined. In addition, revised diagnostic criteria for the Chinese population was proposed in 2023, we aimed to explore their utility in clinical practice at a rare lung disease center. Methods We retrospectively analyzed the data of 100 consecutive patients with BHD diagnosed according to the revised Chinese BHD criteria, encountered at the First Affiliated Hospital of University of Science and Technology of China from Jan 2017 to June 2023. Results There were 100 patients (including 63 females) from 65 unrelated families in Eastern China, mostly Anhui Province. The common manifestations were pulmonary cysts (99%), pneumothorax (60%), and skin lesions (77%). Renal cancer and renal angiomyolipoma were detected in 5 patients each. 37% of patients had no family history of BHD. In total, 25 FLCN germline mutations were detected, including 6 novel mutations. In addition to hotspot mutation c.1285delC/dupC (17%), the most common mutations were c.1015 C > T (16%), c.1579_1580insA (14%), and exons 1–3 deletion (11%) in FLCN. Higher risk of pneumothorax was associated with exons 1–3 deletion mutation and c.1177-5_1177-3de1CTC compared to the hotspot mutation c.1285dupC (91% [95% CI: 0.31, 46.82, p = 0.015] and 67% [95% CI: 0.35, 71.9, p = 0.302] vs. 30%, respectively). The average delay in diagnosis was 7.6 years after initial symptoms. Chinese diagnostic criteria were mostly consistent with typical pulmonary presentations with supportive genetic evidence. Conclusion In the Eastern Chinese region, patients with BHD present most commonly with pulmonary cysts associated with pneumothorax and skin lesions. However, low incidence of renal cancer along with unexpected renal angiomyolipoma was observed. Genotypic spectrum differed from that reported from other global regions, and genotype association of pneumothorax warrants further research. The revised Chinese criteria for BHD seem more appropriate in diagnosing BHD in Chinese patients.

Abstract Background The pathogenic variants responsible for Birt-Hogg-Dubé syndrome (BHDS) in folliculin (FLCN) gene mostly consist of point mutations. Although large intragenic deletions/duplications have been reported in several case reports, the relationship between large intragenic deletions/duplications and phenotype in BHDS remains unclear. Methods We retrospectively identified and reviewed patients with a large intragenic deletion spanning exons 1–3 and analyzed their phenotypic features to compare with those of point mutation carriers in our hospital from January 1, 2017 to August 31, 2022. Results Twenty unique point mutations (including 4 novel mutations) were detected in 62 patients from 45 families (90%). Exons 1–3 deletion were identified in 8 patients from 5 families (10%) that resided in the same region, Feidong County of Anhui Province, China. Breakpoint analysis indicated that all the deletion breakpoints were flanked by Alu repeats. The prevalence of exons 1–3 deletion carriers in Feidong County was 8.1-times higher than that for BHDS in Anhui Province, suggesting a clustered phenomenon of exons 1–3 deletion. Significantly increased risk of pneumothorax was observed in those with exons 1–3 deletion compared with point mutations (91% vs. 58%, p value 0.047). The risk of renal cancer may be higher in those with exons 1–3 deletion than for those with point mutations (18% vs. 4%, p > 0.05). Conclusions Large intragenic deletion of exons 1–3 in FLCN was identified as a local aggregation phenomenon in Feidong County, China, and was associated with a significantly higher risk of pneumothorax compared to those with point mutations.

Abstract Background Chronic obstructive pulmonary disease (COPD) is a respiratory disease that causes a wide range of cognitive impairments. Although COPD-Smoking comorbidity is common, the relationship between smoking and cognitive function in COPD-Smoking comorbidity remains unclear. This study aimed to investigate the effect of smoking on cognitive function like attention in COPD-Smoking patients. Methods In this study, we used the Montreal Cognitive Assessment (MoCA) scale and resting-state functional magnetic resonance imaging (fMRI) to explore the effect of smoking on attention in patients with COPD. Results Behavioral analysis revealed that among patients with COPD the smokers had a shorter course of COPD and showed a worse attention performance than the non-smokers. Resting-state fMRI analysis revealed that among patients with COPD smokers showed lower regional homogeneity (ReHo) value of the fusiform gyrus than non-smokers. Importantly, the ReHo of the fusiform gyrus is positively associated with attention and mediates the effect of smoking on attention in COPD. Conclusions In summary, our study provides behavioral and neurobiological evidence supporting the positive effect of smoking on attention in COPD. This may be helpful for understanding and treating COPD and even other diseases comorbid with smoking.