Summary Background: Crohn's disease affects people world‐wide, but the incidence in Asia is lower than in Western countries. This difference may be due to genetic and/or environmental factors. Three single nucleotide polymorphisms (SNPs) of the NOD2/CARD15 gene have been identified to be independently associated with the development of Crohn's disease in Caucasians. Whether these SNPs are involved in the pathogenesis of Crohn's disease in the Chinese population is unknown. Aim: To determine if NOD2/CARD15 gene polymorphisms are found in Chinese patients with Crohn's disease. Methods: Sixty‐five consecutive Chinese Crohn's disease patients had genotyping performed using sequence‐specific PCR directed against the wild‐type and the Arg702Trp, Gly908Arg and 3020insC variants of the NOD2/CARD15 gene. Controls consisted of 63 patients with ulcerative colitis and 70 patients with dyspepsia. Results: None of the patients with Crohn's disease had heterozygous or homozygous SNP variants. Similarly none of the ulcerative colitis or dyspeptic controls had these SNPs. Conclusion: The three previously described SNPs associated with the development of Crohn's disease in Caucasians are not found in Chinese patients with Crohn's disease.

Owing to the difficulties in isolating the virus and the lack of routine surveillance, the clinical significance of human parainfluenza virus 4 (HPIV-4) is less well defined than that of the other human parainfluenza viruses. We describe the first outbreak of HPIV-4 infection in a developmental disabilities unit, involving 38 institutionalized children and three staff members, during a 3-

Summary Plasma DNA fragmentomics is an emerging area in cell-free DNA diagnostics and research. In murine models, it has been shown that the extracellular DNase, DNASE1L3, plays a role in the fragmentation of plasma DNA. In humans, DNASE1L3 deficiency causes familial monogenic systemic lupus erythematosus with childhood onset and anti- ds DNA reactivity. In this study, we found that human patients with DNASE1L3 disease-associated gene variations showed aberrations in size and a reduction of a “CC” end motif of plasma DNA. Furthermore, we demonstrated that DNA from DNASE1L3-digested cell nuclei showed a median length of 153 bp with CC motif frequencies resembling plasma DNA from healthy individuals. Adeno-associated virus-based transduction of Dnase1l3 into Dnase1l3 -deficient mice restored the end motif profiles to those seen in the plasma DNA of wild-type mice. Our findings demonstrate that DNASE1L3 is an important player in the fragmentation of plasma DNA, which appears to act in a cell-extrinsic manner to regulate plasma DNA size and motif frequency.