RESUMEN
Several mutations in the surfactant protein C (SP-C) gene (SFTPC) have been reported as causing familial pulmonary fibrosis (FPF). However, the genetic background and clinical features of FPF are still not fully understood. We identified one Japanese kindred, in which at least six individuals over three generations were diagnosed with pulmonary fibrosis. We examined the patients radiologically and histopathologically and sequenced their SFTPC and ABCA3 genes. We also established a cell line stably expressing the mutant gene. All the patients had similar radiological and histopathological characteristics. Their histopathological pattern was that of usual interstitial pneumonia, showing numerous fibroblastic foci even in areas without abnormal radiological findings on chest high-resolution computed tomography. No child had respiratory symptoms in the kindred. Sequencing of SFTPC showed a novel heterozygous mutation, c.298G>A (G100S), in the BRICHOS domain of proSP-C, which co-segregated with the disease. However, in the ABCA3 gene, no mutation was found. In vitro expression of the mutant gene revealed that several endoplasmic reticulum stress-related proteins were strongly expressed. The mutation increases endoplasmic reticulum stress and induces apoptotic cell death compared with wild-type SP-C in alveolar type II cells, supporting the significance of this mutation in the pathogenesis of pulmonary fibrosis.
Asunto(s)
Pueblo Asiatico/genética , Estrés del Retículo Endoplásmico/genética , Mutación Puntual/genética , Fibrosis Pulmonar/genética , Proteína C Asociada a Surfactante Pulmonar/genética , Transportadoras de Casetes de Unión a ATP/genética , Adolescente , Sustitución de Aminoácidos/genética , Apoptosis/genética , Biopsia , Salud de la Familia , Femenino , Células HEK293 , Humanos , Masculino , Linaje , Fibrosis Pulmonar/etnología , Fibrosis Pulmonar/patologíaRESUMEN
BACKGROUND: The association between environmental tobacco smoking (ETS) and childhood pneumonia has not been established in developed or developing countries. A study was conducted to assess the effect and impact of ETS exposure on pneumonia among children in central Vietnam. METHODS: A population-based large-scale cross-sectional survey was conducted covering all residents of 33 communes in Khanh Hoa Province, the central part of Vietnam. Information on demographics, socioeconomic status and house environment, including smoking status of each household member, was collected from householders. Hospital admissions for pneumonia among children aged <5 years in each household in the previous 12 months were recorded based on caregiver's report. RESULTS: A total of 353 525 individuals living in 75 828 households were identified in the study areas. Of these, 24 781 (7.0%) were aged <5 years. The prevalence of ETS was 70.5% and the period prevalence of hospital admissions for pneumonia was 2.6%. Multiple logistic regression analysis showed that exposure to ETS was independently associated with hospital admissions for pneumonia (adjusted odds ratio 1.55, 95% CI 1.25 to 1.92). The prevalence of tobacco smoking was higher among men than women (51.5% vs 1.5%). It is estimated that 28.7% of childhood pneumonia in this community is attributable to ETS. CONCLUSIONS: Children in Vietnam are exposed to substantial levels of ETS which results in 44 000 excess hospital admissions due to pneumonia each year among children aged <5 years.