Background: Thromboembolism is less common in children than in adults, but it is frequently associated with Mycoplasma pneumoniae infection in many cases. This study aimed to investigate the clinical characteristics of pediatric M. pneumoniae pneumonia complicated with thromboembolism.Methods: Hospitalized patients with M. pneumoniae pneumonia complicated by thromboembolism were enrolled from January 2012 to December 2021 in Beijing Children's Hospital, Capital Medical University, China. The data on clinical manifestations, laboratory tests, and treatment were evaluated. Results: A total of 49 cases were enrolled, with a mean age of 7.9 years old, including 27 boys and 22 girls. Consolidation of pulmonary lobe or segment was observed in 95.9% (47/49) of the cases, whereas interstitial change was found only in two patients; 85.7% (42/49) of patients had pleural effusion. Pulmonary vascular thromboembolism was most common in 35 patients, whereas 13 cases had thromboembolism of multiple anatomic sites. The levels of Creaction protein, lactate dehydrogenase, and erythrocyte sedimentation rate were all increased, with a mean value of 54.08 ± 52.27 g/L, 451.12 ± 218.76 U/ L, 43.40 ± 29.43 mm/h, respectively. Blood coagulation test showed that all 49 patients had elevated D-dimer values (median 3.81 ng/ml, range, 0.34-48 ng/ml) and normal PT. aPTT.LA was positive in 74.3% (26/35) of the cases. aCL-IgM was positive in 66.7% (26/39) of the cases. aβ2GPI-IgM was positive in 79.4% (27/34) of the cases. The prognosis was generally good in this group. Conclusion:Pulmonary arteriovenous thromboembolism is the most common thromboembolism complicated in MPP, and cerebral artery embolism and cardiac thrombosis are common in extrapulmonary thromboembolism. In the cases of MPP with thromboembolic complications, pulmonary consolidation with pleural effusion is the main characteristic. About two thirds of the cases are positive for antiphospholipid antibodies.

The high clinical and genetic heterogeneity makes it difficult to reach a confirmative diagnosis of suspected pediatric respiratory inherited diseases. Many patients with monogenic respiratory disorders could be missed without genetic testing. We performed a single‐center study in Beijing Children's Hospital to demonstrate the clinical utility of exome sequencing (ES) as a first‐tier test by evaluating the diagnostic yields of ES for inherited diseases with respiratory symptoms. A total of 107 patients were recruited in this study. We identified 51 pathogenic or likely pathogenic variants in 37 patients by ES (with or without copy number variants sequencing). The overall diagnostic yield was 34.6% (37/107). The most frequent disorders in our cohort were primary immunodeficiency disease (PIDs) (18/37, 48.6%) and primary ciliary dyskinesia (PCD) (9/37, 24.3%). We further reviewed the directive outcomes of genetic testing on the 37 positive cases. Our study demonstrated the effectiveness of ES as a first‐tier test in China for diagnosing monogenic diseases of the respiratory system. In the era of precision medicine, ES as a first‐tier test can rapidly make a molecular diagnosis and direct the intervention of the positive cases in pediatric respiratory medicine.