Recessively inherited deletions/duplications and point mutations in the parkin gene are the most common cause of early-onset parkinsonism known so far, but in an increasing number of studies, genetic variations in the serine/threonine kinase domain of the PINK1 gene are found to explain early-onset parkinsonism.
Using serial (18)F-dopa PET, the present longitudinal study addresses rates of progression of nigrostriatal dysfunction in both compound heterozygous (parkin-linked parkinsonism) and single heterozygous parkin gene carriers.
The parkin gene on chromosome 6q and loci on chromosome 1p35-36 and 1p36 are responsible for some cases of autosomal recessive early-onset parkinsonism, but they do not appear to influence susceptibility or variability of age at onset for idiopathic PD.
In conclusion, we described a new PARKIN truncating mutation associated with an early onset parkinsonism, and the presence of foot dystonia as the initial symptom.
Autosomal recessive parkin (PARK2) gene-related parkinsonism may be phenotypically and pathophysiologically distinct from idiopathic Parkinson's disease (PD).
Clinicians should be aware that patients carrying a parkin gene mutation may present with dystonia-parkinsonism or very subtle parkinsonism with a markedly varied age of onset.
Linkage and haplotype analysis using markers in 6q25.2-27 indicated that Parkinsonism in the pedigrees is linked to the parkin gene (maximum LOD-score of 3.85) but that they carry two different mutant haplotypes.
Autosomal recessive mutations in the parkin gene (PARK2) have been identified as a common cause of familial and also sporadic, early-onset parkinsonism (EOPD): point mutations, exonic deletions, and duplications or triplications have been described.
Loss of function of the parkin gene (PRKN) is the predominant genetic cause of juvenile and early-onset parkinsonism in Japan, Europe, and the United States.
In this study no one of our 85 patients of Serbian origin with young-onset (</= 45 years) dopa-responsive parkinsonism (YOP), previously proved negative for PARK1 and PARK2 mutations, had either spinocerebellar ataxia type 2 (SCA2) or SCA3 mutation.
Parkin gene mutations are reported to be a major cause of early-onset parkinsonism (age at onset < or = 45 years) in families with autosomal recessive inheritance and in isolated juvenile-onset parkinsonism (age at onset <20 years).