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Biomedical subjects

S Frucht

Publications and source records attributed to S Frucht.

At least 19 recordsLinked to original sources

Evidence for familial aggregation of tremor in normal individuals.

BACKGROUND: Tremor occurs in most normal individuals, and this tremor may offer basic clues about the mechanisms of neuromuscular control. It is not known whether genetic factors influence the magnitude of tremor in normal families. OBJECTIVE: To assess the familial aggregation of tremor in normal families. METHODS: Control subjects from the Washington Heights-Inwood community in northern Manhattan, NY, were enrolled in a family study. These subjects and their first- and second-degree relatives underwent a videotaped tremor examination. Two neurologists rated the severity of tremor on the videotaped examination, assigning a total tremor score (0 to 36 [maximum]). Associations between the control subjects' and their relatives' total tremor scores were assessed using correlation coefficients and linear regression analysis. In addition, maximum likelihood methods were used to fit a linear mixed-effects model to the total tremor scores of probands and their siblings, after excluding any relatives with essential tremor. RESULTS: There were 56 control subjects and 226 relatives. Tremor was clinically detectable in 221 (97.8%) of 226 relatives. There was an association between the control subjects' total tremor scores and those of their siblings (r = 0.40; p = 0.018), those of all of their first-degree relatives (siblings and children combined, r = 0.20; p = 0.037), but not those of their second-degree relatives (r = 0.002; p = 0.99). In analyses of probands and normal siblings, the estimate of the variance of the family-specific component of the age-adjusted total tremor score was different from zero (p < 0.005), and the family specific component was estimated to account for 52% of the variability in the scores. CONCLUSIONS: Tremor aggregates in normal families, suggesting that genetic factors may contribute to its etiology. Other studies might be designed by investigators to identify these genes through genetic linkage or association analysis. Identification of such genes would help to elucidate the mechanisms underlying this ubiquitous condition.

Adult↗

Mild tremor in relatives of patients with essential tremor: what does this tell us about the penetrance of the disease?

BACKGROUND: Mild tremor may occur in relatives of patients with essential tremor (ET). However, this phenomenon has not been studied quantitatively or with a comparison group. Such a study may provide information on the penetrance of ET. OBJECTIVE: To obtain data on the magnitude of tremor in case and control relatives who did not meet diagnostic criteria for ET. METHODS: Cases with ET and control subjects from the Washington Heights-Inwood community in northern Manhattan, NY, were enrolled in a family study. Their first- and second-degree relatives underwent a videotaped tremor examination. Two neurologists rated the severity of tremor, assigning a total tremor score (0-36 [maximum]). Data were analyzed on 201 case relatives and 212 control relatives who did not meet diagnostic criteria for ET. RESULTS: The mean total tremor score of first-degree case relatives was higher than that of first-degree control relatives (4.9 vs 3.9; P<.003). Total tremor scores for second-degree relatives did not differ (4.1 vs 4.2; P =.68). A larger percentage (55.2% vs 36.6%; P =.01) of first-degree case relatives had total tremor scores of 4 or more. Among first-degree relatives who were older than 60 years, 13 case relatives (59.1%) and 18 control relatives (45.0%) had total tremor scores of 4 or more. CONCLUSIONS: A considerable number of seemingly normal case relatives may have a genetic predisposition for tremor. Even among older case relatives (> or =60 years of age), there was an increased prevalence of higher tremor scores, suggesting that in that age group, subclinical ET may be present and penetrance still may not be complete.

Adult↗

Risk of tremor and impairment from tremor in relatives of patients with essential tremor: a community-based family study.

Essential tremor (ET) is a common condition that is present in as many as 23% of elderly individuals. Our objective was to determine the risk of ET and to study the impairment resulting from ET among relatives of ET cases compared to relatives of controls. ET cases and matched controls from the Washington Heights-Inwood community, New York, and their first- and second-degree relatives underwent a standardized tremor examination. The risk of having ET in relatives of cases vs relatives of controls was compared using Cox proportional hazards models. Five hundred ninety-one subjects were examined (59 ET cases, 72 controls, 234 case relatives, and 226 control relatives). ET was present in 25 (22.5%) of the 111 first-degree relatives of cases compared to 6 (5.6%) of 107 first-degree relatives of controls [relative risk (RR) = 4.67, 95% confidence interval (CI) = 1.90-11.49, p = 0.0008]. RRs were higher in relatives of cases with onset < or =50 years than in those with later onset (RR = 10.38 vs 4.82). Sixteen (64%) of twenty-five affected first-degree case relatives exhibited moderate tremor while performing tasks such as writing, drinking, or pouring. Relatives of ET patients are five times more likely to develop the disease than are members of the population and ten times more likely if the proband's tremor began at an early age. The majority of the affected relatives can expect to experience impairment resulting from tremor.

Adolescent↗

A major locus for myoclonus-dystonia maps to chromosome 7q in eight families.

Myoclonus-dystonia (M-D) is an autosomal dominant disorder characterized by myoclonic and dystonic muscle contractions that are often responsive to alcohol. The dopamine D2 receptor gene (DRD2) on chromosome 11q has been implicated in one family with this syndrome, and linkage to a 28-cM region on 7q has been reported in another. We performed genetic studies, using eight additional families with M-D, to assess these two loci. No evidence for linkage was found for 11q markers. However, all eight of these families showed linkage to chromosome 7 markers, with a combined multipoint LOD score of 11.71. Recombination events in the families define the disease gene within a 14-cM interval flanked by D7S2212 and D7S821. These data provide evidence for a major locus for M-D on chromosome 7q21.

Chromosome Mapping↗

Dental age in southwest Germany. A radiographic study.

A cross-sectional study was undertaken in order to assess the dental age of healthy Southwest German boys and girls between the ages of 2 and 20 years by evaluating 1,003 panoramic radiographs. Dental age was assessed according to the method of Demirjian et al. All permanent teeth of the lower left jaw except the third molar were rated, the development of each tooth was divided into 8 defined stages. Statistical evaluation revealed a correlation between the parameters chronological age and score sum of r = 0.85 for girls and r = 0.89 for boys. The values of the score sum in relation to chronological age were distributed as in a logistic function. Two gender-specific equations for calculating dental age were devised and a marked sexual dimorphism was found. With the beginning of root formation, the girls showed accelerated development. The fact that dental age distribution in Southwest Germany is not significantly correlated to that of a French-Canadian collective underlines Demirjian's demand for regional standards of dental development to be calculated using his score system.

Adolescent↗

Myoclonus.

The diagnosis and treatment of myoclonus pose a particular challenge to the neurologist. Few well-controlled double-blind studies of antimyoclonic agents have been performed, and clinical rating of the effectiveness of treatment has been primarily descriptive. As a result, therapy is often empiric. This article reviews the author's approach to treating patients with myoclonus. Three principles guide treatment. First, the cause and physiology of the myoclonic jerks must be ascertained before choosing the appropriate therapy. Second, multiple drugs often must be used in combination to achieve functional improvement. Third, given the paucity of adequately controlled trials, the treating physician must rely on well-documented case series of patients with myoclonic syndromes who obtained benefit from a drug.

Journal Article↗

Falling asleep at the wheel: motor vehicle mishaps in persons taking pramipexole and ropinirole.

The authors report a new side effect of the dopamine agonists pramipexole and ropinirole: sudden irresistible attacks of sleep. Eight PD patients taking pramipexole and one taking ropinirole fell asleep while driving, causing accidents. Five experienced no warning before falling asleep. The attacks ceased when the drugs were stopped. Neurologists who prescribe these drugs and patients who take them should be aware of this possible side effect.

Aged↗