Increased tremor severity in bilineal essential tremor: a report of two families.

Up to 6% of the general population have essential tremor (ET). In a number of couples both partners may have ET. The clinical profile of ET in children and the parents where both parents and the child have ET remains to be established. We report on two families where both parents and one child have ET. The severity of ET was greater in the children than in either parent. Such families could provide special opportunity to determine relation between genotype and phenotypic expression of ET.