Previous molecular characterization of Mycoplasma pneumoniae in China focused only on one or two cities. In this study, we characterized 835 samples from patients suspected to be infected with M. pneumoniae; these samples were collected in 2016 from pediatric patients from different regions of China. Multiple locus variable number tandem repeat analysis (MLVA), P1-restriction fragment length polymorphism (RFLP) analysis, and sequencing of the domain V of 23S rRNA were performed to compare genotype distribution across different locations. Two-hundred-and-thirteen samples tested positive for M. pneumoniae by PCR. P1 types were identified in 154 samples: 78.6% were type I and 21.4% were type II. Type I was the most prevalent genotype in five locations, except Nanjing where type II was the most common type (p < 0.01). Five distinct MLVA types were identified in the 172 samples. Genotype M4-5-7-2 was predominant at all locations, except Nanjing where type 3-5-6-2 was the most common (p < 0.01). Macrolide resistance-associated mutations were identified in 186 (76.3%) samples. The resistance rate differed with the location. This study showed that genotypes and macrolide resistance rate differed across China. The most prevalent genotype in China remains M4-5-7-2/P1-1. The resistance rate decreased, along with changes to the M4-5-7-2 genotype.

A genome-wide association study (GWAS) suggested that variants on chromosome 17q21 were associated with childhood-onset asthma in white populations. Two replication studies had been conducted in southern Han Chinese population in 2009 and 2012. However, these two Chinese replication results were inconsistent. To further confirm the role of 17q21 common variants, an association study of 17q21 single nucleotide polymorphisms (SNPs) with the risk of childhood-onset asthma was performed in a Han population from northeastern China. In this study, rs3894194, rs12603332 and rs11650680 were genotyped in 435 asthmatic children and 601 healthy controls by using a SNaPshot method. Our data showed that the allelic frequency of rs12603332 and rs11650680 showed significant differences between asthmatic cases and healthy controls, with an odds ratio (OR) of 1.36 [95% confidence interval (CI) 1.12-1.65, P=0.002] and an OR of 1.36 (95% CI 1.07-1.74, P=0.01). Genotype distribution analysis also showed the significant associations of the above two loci with childhood asthma under dominant, recessive and additive model (dominant OR=1.57, 95% CI 1.04-2.36, P=0.032; recessive OR=1.41, 95% CI 1.09-1.83, P=0.009; additive OR=1.97, 95% CI 1.24-3.14, P=0.004; recessive OR=1.50, 95% CI 1.13-1.98, P=0.005). Besides, linear regression analysis showed that rs3894194 and rs12603332 were also significantly associated with asthma phenotypes such as log10 -transformed immunoglobulin E (IgE) level (IU/ml) and log10 -transformed eosinophil percentage (dominant, P=0.04; additive, P=0.01; recessive, P=0.04; recessive, P=0.03; additive, P=0.02). Collectively, our findings suggest that orosomucoid 1-like 3 (ORMDL3) locus on chromosome 17q21 is a risk factor for childhood-onset asthma in northeastern Han Chinese population. Further studies will be needed to elucidate the pathogenesis that ORMDL3 locus predisposes to childhood-onset asthma.

Our findings first suggested that the variants in RAD50-IL13 region were not associated with asthma risk in Northeastern Han Chinese children.

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Attention deficit hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders, with an estimated worldwide prevalence of approximately 5% in school-age children.(1) It is characterised by developmentally inappropriate symptoms of inattention, hyperactivity and/or impulsivity, with the onset before the age of seven years.