Almost all human diseases have been shown to aggregate familially to some degree. This familiality is generally taken as evidence for the existence of a genetic etiologic mechanism or environmental factors common to family members, or a combination of both. It has been argued that for a disease with strong familial aggregation, environmental risk factors alone are unlikely to account for such s...

OBJECTIVE Our aim was to evaluate familial aggregation of migraine in a large group of Portuguese families, and to assess if familial aggregation differs between MA and MO. METHODS Familial aggregation was evaluated by estimating relative risk (RR) of migraine in 143 first-degree relatives of 50 probands with MA, in 196 first-degree relatives of 94 probands with MO and also in proband's spous...

BACKGROUND Essential tremor (ET) is often familial and phenotypic features may be shared within families. Cranial (neck, voice, and jaw) tremor is an important feature of ET. We examined whether cranial tremor aggregates in ET families, after controlling for other factors (age, tremor severity, and duration). METHODS Among ET probands and relatives enrolled in a genetic study at Columbia Univ...

BACKGROUND Although the hallmark feature of essential tremor (ET) is kinetic tremor, patients may exhibit additional motor features (e.g., intention tremor and mild gait ataxia) that are markers of an underlying abnormality of cerebellar function. ET is also a highly familial disorder, but we do not know whether the presence and expression of cerebellar signs are similar across family members. ...

BACKGROUND There is increasing evidence that substance use disorders are familial and that genetic factors explain a substantial degree of their familial aggregation. To perform a controlled family study of probands with several different predominant drugs of abuse, including opioids, cocaine, cannabis, and/or alcohol. METHODS The subjects for the present study included 231 probands with depe...

Family studies throughout the 1970s and 1980s documented the role of shared genetic factors in the familial aggregation of cardiovascular disease and its risk factors, including hypertension. These familial aggregation studies, however, do not identify and characterize the role of particular genes. Identification of the genes contributing to interindividual variation in disease risk may facilit...