Objectives: To evaluate the relationship between point mutations within the parkin gene and essential tremor (ET).
Background: Essential tremor, the most common movement disorder, has long been recognised as an autosomal dominant disease. To date the genes involved in ET pathogenesis are still unknown. Several authors reported the association of ET with Parkinson's disease (PD).
Patients and methods: One hundred and ten unrelated ET patients were analysed for point mutations within the parkin gene. Experimental conditions for DHPLC mutational analysis of the coding region of the parkin gene were set up.
Results: Neither obvious disruptive mutations, nor mutations previously described in patients with Parkinson's disease were identified in the cohort of patients analysed. DHPLC analysis detected two already reported polymorphisms [c.1138G>C (V380L) and c.1180G>A (D394N)], and four novel rare variants (frequency <1%) [c.645C>A (H215Q); c.847C>T (H279H); c.1393G>A (V465M) and c.2695A>G] located within exonic regions. Four new polymorphisms [c.413-20T>C; c.872-35G>A; c.872-68C>G; c.1286-117A>G], and one rare variant (c.934-3C>T) were also found within intronic regions.
Conclusion: Causative sequence variants in the parkin gene have not been identified in this cohort of Italian ET patients.