Linkage of Familial Essential Tremor to Chromosome 5Q35

BACKGROUND:Essential tremor is a neurological condition characterized by tremor during voluntary movement. To date, 3 loci linked to familial essential tremor have been identified. METHODS:We examined 48 essential tremor patients in 5 large essential tremor pedigrees in our data set for genetic linkage using an Affymetrix Axiom array. Linkage analysis was performed using an affecteds-only dominant model in SIMWALK2. To incorporate all genotype information, GERMLINE was used to identify genome segments shared identical-by-descent in pairs of affecteds. Exome sequencing was performed in pedigrees showing evidence of linkage. RESULTS:For one family, chromosomes 5 and 18 showed genome-wide significant linkage to essential tremor. Shared segment analysis excluded the 18p11 candidate region and reduced the 5q35 region by 1 megabase. Exome sequencing did not identify a potential causative variant in this region. CONCLUSION:A locus on chromosome 5 is linked to essential tremor. Further research is needed to identify a causative variant. © 2016 International Parkinson and Movement Disorder Society.