# Parkinsonism in Gerstmann-Sträussler-Scheinker disease: A case report

## TL;DR

A Colombian woman with Gerstmann-Sträussler-Scheinker disease showed atypical parkinsonism symptoms, highlighting the disease's varied presentation and the need for genetic testing.

## Contribution

This case expands the known phenotypic spectrum of PRNP P102L-associated GSS with a parkinsonism presentation and no ataxia.

## Key findings

- The P102L mutation in the PRNP gene was identified in a family with GSS, showing a homogeneous parkinsonian phenotype.
- Parkinsonism was the initial symptom in this case, with no ataxia, an atypical presentation for GSS.
- The case highlights the underdiagnosis of GSS in Latin America due to limited access to genetic testing.

## Abstract

Autosomal dominant prion diseases of the central nervous system, including Gerstmann-Sträussler-Scheinker disease (GSS), Creutzfeldt-Jakob disease, and fatal familial insomnia, are caused by mutations in the PRNP gene. These conditions exhibit highly variable clinical and pathological features, making diagnosis challenging, with poor survival outcomes. In Colombia, the incidence of prion diseases remains unknown. We report a case of GSS with parkinsonism, a rare presentation, emphasizing intrafamilial variability with the same pathogenic variant, underscoring the importance of reporting each case.

A 55-year-old woman from Colombia presented with symptoms of instability, rigidity, and bradykinesia. Over one year, her condition progressed to cognitive decline, dysphagia, and severe motor impairment. Differential diagnostic studies were conducted. A pathogenic P102L mutation in the PRNP gene was identified, confirming an autosomal dominant inheritance pattern. Symptomatic management and interdisciplinary rehabilitation were initiated. This mutation led to the diagnosis of at least 10 symptomatic family members and allowed for genetic counseling of asymptomatic relatives.

This case of GSS with the P102L mutation demonstrates a late onset and rapid progression with atypical parkinsonism presentation, without ataxia, which is predominantly reported in previous cases. The familial segregation of this mutation highlights the importance of monitoring and following at-risk relatives. While the disease remains incurable, knowledge of genetic predisposition allows for better family planning and appropriate medical support, improving quality of life and emotional support.

•Underdiagnosis of GSS persists in Latin America due to limited genetic access.•GSS P102L case with parkinsonism as initial symptom and absence of ataxia.•Atypical phenotype supports need to consider GSS in early parkinsonism.•This case expands the phenotypic spectrum of PRNP P102L-associated GSS.•Homogeneous parkinsonian phenotype observed across multiple family members.

Underdiagnosis of GSS persists in Latin America due to limited genetic access.

GSS P102L case with parkinsonism as initial symptom and absence of ataxia.

Atypical phenotype supports need to consider GSS in early parkinsonism.

This case expands the phenotypic spectrum of PRNP P102L-associated GSS.

Homogeneous parkinsonian phenotype observed across multiple family members.