Novel PRNP sequence variant associated with familial encephalopathy.

Area of Science:

• Neurogenetics
• Prion Diseases
• Molecular Neurology

Background:

• Human transmissible spongiform encephalopathies (TSEs) are progressive neurodegenerative disorders with hereditary, infectious, or sporadic origins.
• Hereditary forms of TSEs are linked to mutations in the PRNP gene.
• Gerstmann-Sträussler-Scheinker disease is a rare inherited prion disease.

Purpose of the Study:

• To investigate the genetic basis of a familial neurodegenerative disorder.
• To identify the specific genetic mutation responsible for the observed symptoms in a family.
• To determine the pathogenic role of the identified mutation in TSEs.

Main Methods:

• Clinical evaluation of seven affected family members presenting with ataxia, dysarthria, myoclonic jerks, and cognitive decline.
• Neuroimaging (cerebellar atrophy) and electroencephalogram (periodic discharges) analysis.
• PRNP gene sequencing to identify mutations in affected and unaffected individuals, and controls.

Main Results:

• A novel H187R mutation in the PRNP gene was identified in all affected family members.
• This mutation was absent in unaffected family members and unrelated controls.
• Clinical presentation and diagnostic findings were consistent with a familial encephalopathy resembling Gerstmann-Sträussler-Scheinker disease.

Conclusions:

• The novel H187R PRNP gene mutation is strongly associated with the familial neurodegenerative disorder observed.
• This mutation likely plays a pathogenic role in the development of this form of human transmissible spongiform encephalopathy.
• The findings contribute to the understanding of genetic TSEs and PRNP gene mutations.