HOMER1 promoter analysis in Parkinson's disease: association study with psychotic symptoms.

AIMS:HOMER1 gene expression has been linked to abnormal movements in animals receiving chronic administration of antipsychotics. The continuing neurodegeneration of Parkinson's disease (PD) and the prolonged use of L-dopa are associated with motor complications, such as dyskinesia, and psychotic side effects, including hallucinations and paranoid delusions. Approximately 25-40% of patients with idiopathic PD experience hallucinations. Genetic variability within different candidate genes has been implicated in the clinical severity of sporadic PD in many populations. MATERIALS AND METHODS:We investigated 3 polymorphisms located in the 5' flanking region of the HOMER1 gene within a sample of 131 sporadic PD patients from southern Italy, using a 3-SNP genotype and haplotype combination (rs4704559, rs10942891, rs4704560). RESULTS:Our study implicates the effects of allele A of the rs4704559 marker in susceptibility to psychotic symptoms in PD (chi2 = 8.092, 1 d.f., p = 0.004). CONCLUSION:Even though our results are preliminary, this HOMER1 gene variant may represent a biomarker for side effect evaluation in PD patients.