We are grateful to all patients and their parents for participation in this study. We thank Petra Badorf and Daniela Hemmeter for excellent technical assistance. We acknowledge Klaus Griewank for critically reviewing the manuscript. The study was partly supported by a grant from the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung (BMBF); project ANCYLOSS, TP5).

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Since late 2012, coxsackievirus A6 (CVA6) has gradually become the predominant pathogen responsible for hand-foot-mouth disease (HFMD) in several provinces of China. A total of 626 patients diagnosed with HFMD in Shanghai, China from January 2012 to September 2013 were enrolled in this study. Of these, 292 CVA6 infected cases were subjected to clinical analyses. Whole-genome sequencing, recombination and phylogenetic analyses were also performed. A recombinant CVA6 monophyletic lineage was found during an outbreak of CVA6-associated HFMDs in Shanghai, China in November 2012, and accounted for 21.9% (64/292) of the CVA6 strains during the study period. Recombination analyses showed that the 2C gene of the novel CVA6 virus was probably derived from a coxsackievirus A4 (CVA4) strain circulating in the population. Clinical observation showed that this recombinant CVA6 virus led to a more generalized rash than did the non-recombinant CVA6 virus. This newly emerged CVA6 lineage was associated with a considerable proportion of HFMD cases from 2012 to 2013 in Shanghai, and poses a potential threat to public health.

Geographic tongue (GT) is a benign inflammatory disorder of unknown etiology. Epidemiology and histopathology in previous studies found that generalized pustular psoriasis (GPP) is a factor associated with GT, but the molecular mechanism remains obscure. To investigate the mechanism of GT, with and without GPP, three cohorts were recruited to conduct genotyping of IL36RN, which is the causative gene of GPP. In a family spanning three generations and diagnosed with only GT (“GT alone”), GT was caused by the c.115+6T>C/p.Arg10ArgfsX1 mutation in the IL36RN gene. An autosomal dominant inheritance pattern with incomplete penetrance was observed. In the cohort consisting of sporadic cases of “GT alone” (n = 48), significant associations between GT and three IL36RN variants (c.115+6T>C/p.Arg10ArgfsX1, c.169G>A/p.Val57Ile and c.29G>A/p.Arg10Gln) were shown. In the GPP patient cohort (n = 56) and GPP family member cohort (n = 67), a significant association between the c.115+6T>C mutation and the simultaneous presence of GPP and GT was observed when compared to the presence of GPP without GT (P < 0.05). Biopsies revealed similarities among GT patients with different genotypes (AA, Aa and aa), with the neutrophils prominently infiltrating the epidermis. Western-blot analysis showed that the expression ratio of IL-36Ra/IL-36γ in lesioned tongues with individuals harboring different genotypes (AA, Aa and aa, n = 3, respectively) decreased significantly compared to controls (n = 3). We describe the mechanism of GT for the first time: some cases of GT are caused by IL36RN mutations, while those lacking mutations are associated with an imbalance in expression between IL-36Ra and IL-36γ proteins in tongue tissue.Electronic supplementary materialThe online version of this article (doi:10.1007/s00439-016-1750-y) contains supplementary material, which is available to authorized users.