Response to rituximab in 3 children with opsoclonus-myoclonus syndrome resistant to conventional treatments.

Background:Essential tremor (ET) is the most common movement disorder world-wide. Three susceptibility loci on chromosomes 3q13, 2p24.1, and 6p23 have beenreported, but no causative genes were found. The Ser9Gly variant of dopamine D3receptor (DRD3) receptor was found associated to ET in a French and US popula-tion.Methods:A case–control study to evaluate the association between the Ser9Glyvariant and ET was performed in a cohort of 116 Italian patients with familial ET andin 158 normal controls.Results:No significant difference in allele and genotype fre-quencies was found between the two groups.Conclusions:These results do not supportan association between DRD3 Ser9Gly and susceptibility to ET in Italian patients.