Genetic characterization of measles virus genotype D6 subacute sclerosing panencephalitis case, Alberta, Canada

Area of Science:

• Virology
• Neuroscience
• Genetics

Background:

• Subacute sclerosing panencephalitis (SSPE) is a rare, fatal neurological complication of measles virus (MV) infection, typically acquired in childhood.
• SSPE is characterized by defective MV strains that accumulate extensive mutations, preventing the production of infectious virions.

Observation:

• A full MV genome sequence from a recent SSPE case (genotype D6) was analyzed and compared to other genotype D6 wild-type and SSPE strains.
• The Alberta D6 strain exhibited significant genetic divergence from other reported SSPE D6 sequences.

Findings:

• Mutations were identified across all genes of the Alberta SSPE MV strain.
• The M gene showed the highest sequence variation (17.6% nucleotide, 31% amino acid), while the L gene displayed the least.
• Overall nucleotide variability of the complete genome (15,672 bases) compared to wild-type and other SSPE D6 strains was approximately 3%.

Implications:

• These findings highlight the genetic heterogeneity of MV strains associated with SSPE.
• Understanding these specific mutations may offer insights into SSPE pathogenesis and viral persistence.
• Further research into genotype-specific MV mutations could inform future diagnostic or therapeutic strategies for SSPE.