Kantonsspital St.Gallen

The phenotypic variation of a PARK-Parkin family and the role of heterozygosity

Julia Walch




Parkinson's disease (PD) is a common neurodegenerative disorder with both sporadic occurrence and Mendelian heredity, as it is true for autosomal recessive parkin‐related PD (PARK‐parkin). Parkin‐related PD is characterized by early onset, slow progression, frequent lower limb dystonia, and a robust response to levodopa. Clinicians are increasingly confronted with heterozygous PD patients mimicking dominant inheritance. Nevertheless, the exact clinical implications of heterozygosity are not fully understood.


We present an illustrative PARK‐parkin family with 2 affected sisters (compound heterozygous) and their father (heterozygous). One sister expresses the classical phenotype, whereas the other has isolated jerky tremor. The father has left‐sided action tremor of the hand with some dystonic posturing without clear bradykinesia and normal DaTSCAN.


This case series illustrates the phenotypic variability in parkin‐related PD with 1 classical phenotype and 1 patient with isolated jerky tremor. Unilateral hand tremor of the heterozygous father could mislead genetic testing by mimicking dominant inheritance.
citation Walch J. The phenotypic variation of a PARK-Parkin family and the role of heterozygosity. Movement Disorders Clinical Practice 2019; 2019 Sep:700-703.
type journal paper/review (English)
date of publishing 14-11-2019
journal title Movement Disorders Clinical Practice (2019 Sep/16;6(8))
pages 700-703
DOI 10.1002/mdc3.12826
contact Georg Kägi