Herpes simplex encephalitis in children with autosomal recessive and dominant TRIF deficiency

J Clin Invest. 2011 Dec;121(12):4889-902. doi: 10.1172/JCI59259. Epub 2011 Nov 21.

Abstract

Herpes simplex encephalitis (HSE) is the most common sporadic viral encephalitis of childhood. Autosomal recessive (AR) UNC-93B and TLR3 deficiencies and autosomal dominant (AD) TLR3 and TRAF3 deficiencies underlie HSE in some children. We report here unrelated HSE children with AR or AD TRIF deficiency. The AR form of the disease was found to be due to a homozygous nonsense mutation that resulted in a complete absence of the TRIF protein. Both the TLR3- and the TRIF-dependent TLR4 signaling pathways were abolished. The AD form of disease was found to be due to a heterozygous missense mutation, resulting in a dysfunctional protein. In this form of the disease, the TLR3 signaling pathway was impaired, whereas the TRIF-dependent TLR4 pathway was unaffected. Both patients, however, showed reduced capacity to respond to stimulation of the DExD/H-box helicases pathway. To date, the TRIF-deficient patients with HSE described herein have suffered from no other infections. Moreover, as observed in patients with other genetic etiologies of HSE, clinical penetrance was found to be incomplete, as some HSV-1-infected TRIF-deficient relatives have not developed HSE. Our results provide what we believe to be the first description of human TRIF deficiency and a new genetic etiology for HSE. They suggest that the TRIF-dependent TLR4 and DExD/H-box helicase pathways are largely redundant in host defense. They further demonstrate the importance of TRIF for the TLR3-dependent production of antiviral IFNs in the CNS during primary infection with HSV-1 in childhood.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport / deficiency*
  • Adaptor Proteins, Vesicular Transport / genetics
  • Adaptor Proteins, Vesicular Transport / physiology
  • Amino Acid Sequence
  • Child, Preschool
  • Codon, Nonsense
  • Consanguinity
  • DEAD-box RNA Helicases / physiology
  • Encephalitis, Herpes Simplex / genetics*
  • Female
  • Genes, Dominant
  • Genes, Recessive
  • Genetic Heterogeneity
  • Genetic Predisposition to Disease
  • Genome-Wide Association Study
  • Genotype
  • Herpesvirus 1, Human*
  • Humans
  • Infant
  • Interferon-alpha / biosynthesis
  • Interferon-alpha / genetics
  • Male
  • Molecular Sequence Data
  • Mutation, Missense
  • Pedigree
  • Saudi Arabia
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Signal Transduction / physiology
  • Toll-Like Receptor 3 / physiology
  • Toll-Like Receptor 4 / physiology

Substances

  • Adaptor Proteins, Vesicular Transport
  • Codon, Nonsense
  • Interferon-alpha
  • TICAM1 protein, human
  • TLR3 protein, human
  • TLR4 protein, human
  • Toll-Like Receptor 3
  • Toll-Like Receptor 4
  • DEAD-box RNA Helicases

Associated data

  • GEO/GSE32390