Incidence of AChR Ab-positive myasthenia gravis in Israel: A population-based study.

BACKGROUND: The incidence of myasthenia gravis (MG) has traditionally been low, ranging between 2-6/106 . Several recent epidemiological studies have reported a higher incidence. We, therefore, aimed to assess and characterize the incidence of MG in Israel. METHODS: We retrospectively reviewed the records of all four laboratories that performed the acetylcholine receptor antibody (AChR Ab) test in Israel between 1994 and 2013 and documented the number of newly diagnosed seropositive MG patients each year. To assure that data indeed reflect only newly diagnosed patients, patient's names and ID numbers were screened at the Hadassah medical center database since 1978, the year when the test was first performed in Israel. In order to calculate the annual incidence of the disease, the population at risk was derived from the annual publication of the Israeli Central Bureau of Statistics. RESULTS: The annual incidence of MG for this time period was 13.1/106 inhabitants. The mean incidence of MG between 1994 and 2003 was 7.695/106 /y, while the mean incidence between 2004 and 2013 was 18.49/106 (P < .0001). Mean age of diagnosis between 1994 and 2003 was 56.65 ± 0.9351, while between 2004 and 2013, it was 59.89 ± 0.5336 (P = .0012). Male to female (M:F) incidence ratio in the years 1994-2003 and 2004-2013 was 2:3.2 and 3:1.8, respectively, reflecting increased incidence among males (P < .0001). CONCLUSIONS: The incidence of MG in Israel has increased significantly during the last decade, especially among males of older age. These findings may reflect an etiological role of an environmental factor, increased awareness, and increased longevity in general.

Characterization of movement disorders in patients with familial Creutzfeldt-Jakob disease carrying the E200K mutation.

BACKGROUND: While myoclonus and ataxia are considered common in patients with familial Creutzfeld-Jakob disease (fCJD), other movement disorders are less prevalent. OBJECTIVES: To systemically evaluate the frequency of extrapyramidal signs and movement disorders in patients with fCJD. METHODS: A detailed neurological examination, with special emphasis on movement disorders and extrapyramidal signs, was conducted in 43 consecutive symptomatic CJD patients (26 males and 17 females; mean age 58.7 +/- 8.9 yrs, range 43-77 years) carrying the E200K mutation in the PRNPgene. RESULTS: Limb or gait ataxia was noted in 38 patients (88%) (37 patients, 86%, had ataxia at presentation). Myoclonus was evident in 25/43 patients (58%) (21 patients, 49%, at presentation). In 95% of the patients (41/43) (37/43, 86% at presentation) at least one extrapyramidal sign throughout the disease course was noted, the most prevalent being rigidity (28/43, 65% of the patients; and 22/43, 51% at presentation), followed by the glabellar sign (24/43, 56% of the patients; and 22/43, 51% at presentation), bradykinesia (19/43, 44%; and 15/43, 35% at presentation), dystonia (15/43, 35%; 12/43, 28% at presentation) and tremor (13/43, 30%; 12/43, 28% at presentation). CONCLUSIONS: In this unique population of fCJD patients, myoclonus was less prevalent than previously reported while other extrapyramidal signs were common and occurred at a relatively early stage of the disease. The high prevalence of movement disorders can be added to other phenomena characteristic of this familial disorder among Libyan lews. Whether this is attributable to the E200K mutation itself or to some other mechanism has still to be elucidated.

Presymptomatic signs in healthy CJD mutation carriers.

Creutzfeldt-Jacob disease (CJD) is a rapidly progressing dementia with neurological, psychiatric and cognitive symptoms. We focused our study on the familial CJD form among Libyan Jews (the E200K mutation), trying to identify preclinical neuropsychological signs in mutation carriers to facilitate early diagnosis of the disease. A wide range of neuropsychological tests was administered to 27 healthy volunteers, all first-degree relatives of genetic CJD patients. Thirteen of our participants were gene mutation carriers (E200K) and 14 controls. The healthy mutation carriers reported significantly lower Trait and higher State anxiety scores. Repeated Measure analysis showed statistical significance. The Anxiety Index (State-Trait Anxiety Score) progressed with age in the carriers' group but not in the controls. Since this was more pronounced in the older subjects, we suggest that abnormal stress mechanisms precede the clinical onset of CJD. Cognitive differences have also been found between carriers and controls, especially in visual recognition of pictured objects. Both kinds of differences (anxiety levels and cognitive deficits) were most pronounced in elderly subjects. This study is the first to show any dysfunction in healthy CJD mutation carriers.