Enterovirus 71 (EV71) infection has become one of the major threats to children globally in recent years. Toll-like receptor 3 (TLR3) plays an essential role in host defense against EV71 infection. This study was designed to assess the possible association between the TLR3c.1377C/T polymorphism and disease severity in Chinese children with EV71 infection. The TLR3c.1377C/T gene polymorphism was identified in EV71-infected patients (n = 177), including mild cases (n = 99) and severe cases (n = 78) as well as healthy controls (n = 225), using improved multiplex ligation detection reaction (iMLDR) technology. Serum levels of IFN-γ and IL-4 were measured using enzyme-linked immunosorbent assays. The presence of the TT genotype (p = 0.030) and the T allele (OR, 1.8; 95% CI, 1.2-2.8; p = 0.010) was significantly more frequent in severe cases. The plasma levels of IFN-γ and the IFN-γ/IL-4 ratio were significantly lower with the TT (102.0 ± 24.2 pg/mL, p < 0.01 and 14.2 ± 2.8, p < 0.001) and CT genotypes (114.1 ± 26.2 pg/mL, p < 0.05 and 18.0 ± 3.1, p < 0.001) than with the CC genotype (135.5 ± 36.8 pg/mL and 24.9 ± 4.7), but the plasma levels of IL-4 with the TT (7.3 ± 1.7 pg/mL, p < 0.01) and CT genotypes (6.4 ± 1.3 pg/mL, p < 0.05) were significantly higher than with the CC genotype (5.5 ±1.3 pg/mL). These findings suggest that the TLR3c.1377T allele is associated with susceptibility to severe EV71 infection in Chinese children.

Rett syndrome (RTT) is a rare neurodevelopmental disorder characterized by severe cognitive, social, and physical impairments resulting from de novo mutations in the X-chromosomal methyl-CpG binding protein gene 2 (MECP2). While there is still no cure for RTT, exploring up-to date neurofunctional diagnostic markers, discovering new potential therapeutic targets, and searching for novel drug efficacy evaluation indicators are fundamental. Multiple neuroimaging studies on brain structure and function have been carried out in RTT-linked gene mutation carriers to unravel disease-specific imaging features and explore genotype-phenotype associations. Here, we reviewed the neuroimaging literature on this disorder. MRI morphologic studies have shown global atrophy of gray matter (GM) and white matter (WM) and regional variations in brain maturation. Diffusion tensor imaging (DTI) studies have demonstrated reduced fractional anisotropy (FA) in left peripheral WM areas, left major WM tracts, and cingulum bilaterally, and WM microstructural/network topology changes have been further found to be correlated with behavioral abnormalities in RTT. Cerebral blood perfusion imaging studies using single-photon emission CT (SPECT) or PET have evidenced a decreased global cerebral blood flow (CBF), particularly in prefrontal and temporoparietal areas, while magnetic resonance spectroscopy (MRS) and PET studies have contributed to unraveling metabolic alterations in patients with RTT. The results obtained from the available reports confirm that multimodal neuroimaging can provide new insights into a complex interplay between genes, neurotransmitter pathway abnormalities, disease-related behaviors, and clinical severity. However, common limitations related to the available studies include small sample sizes and hypothesis-based and region-specific approaches. We, therefore, conclude that this field is still in its early development phase and that multimodal/multisequence studies with improved post-processing technologies as well as combined PET–MRI approaches are urgently needed to further explore RTT brain alterations.