OBJECTIVETo summarize the clinical characteristics and long-term prognosis of herpes simplex virus encephalitis (HSE) in childhood and to analyze genotype of UNC93B1 and TLR3.

METHODData of a total of 30 HSE patients admitted to Beijing Children's Hospital from January 2008 to September 2013 were retrospectively analyzed, the data included clinical manifestations, physical sign, auxiliary examination, therapy and long-term clinical prognosis. The family history obtained during follow-up visit was also analyzed for genetic predisposition. With parents' agreement, the blood specimens of patients were collected in EDTA anticoagulant tubes, the first 2 genetic etiologies UNC93B1 and TLR3 were sequenced, and the genetic susceptibility to HSE in childhood was summarized.

RESULT(1) All the 30 patients (100%) had fever, 28 (93%) had seizure, 25 (83%) had altered state of consciousness, only 11 (37%) had personality changes, and in 8 (73%) appeared at or after 2 weeks of onset . (2) During the long-term follow up, 2 (7%) patients died after discharge, 23 patients (82%) had neurological sequelae, 13 patients (57%) had moderate, severe disability and vegetative state. (3) After sequencing of UNC93B1, and TLR3, one patient was found homozygous for a single-nucleotide substitution at position C.414C>G in exon 4 of UNC93B1 which affected the expression of UNC93B1, and may block or decrease the production of interferon. (4) Six single nucleotide polymorphisms (SNPs) were found in this study, their genotype frequency and gene frequency of Chinese were respectively searched in Genomes Project in NCBI and defined 1 000 genomes group. The genotype frequency of UNC93B1 rs7149 between 1 000 genomes group and HSE group was significantly different (χ² = 55.37, P<0.05). The frequency of CC type and C type was higher in HSE group, both of them had significant difference (χ² = 93.90, P<0.05, OR=61.563; χ² = 134.40, P<0.05, OR=12.491).

CONCLUSIONHSE lacks specific clinical manifestations, the long-term prognosis is poor. One HSE patient carrying a heterozygous mutation in UNC93B1 which may lead to the susceptibility to HSE and had harmful effect on long-term prognosis. The SNP UNC93B1 rs7149 may also have relationship with susceptibility to HSE and the children carrying CC genotype or C gene in this gene site maybe more susceptible to HSE.