No abstract

To clarify the role of heredity and of some environment risk factors in the etiology of idiopathic Parkinson's disease, we performed a case-control study in two regions of southern Italy, Campania and Molise. We selected two controls for each parkinsonian patient, the patient's spouse and a sex- and age-matched neurological control. One hundred sixteen consecutive outpatients with Parkinson's disease (77 men, 39 women; mean age +/- SD = 62.5 +/- 9.9) and the same number of spouses and neurological controls were interviewed about five environmental risk factors (cigarette smoking, well-water drinking, head trauma with loss of consciousness, strict diets, general anesthesia) and two genetic risk factors (family history of Parkinson's disease or of essential tremor). Well-water drinking and family history of Parkinson's disease or essential tremor showed a positive association with Parkinson's disease; smoking showed a negative association. The most relevant risk factor was history of familial Parkinson's disease (odds ratio = 14.6; 95% confidence interval = 7.2 - 29.6); 33% of our patients had at least one affected relative. We also showed a unilateral distribution of ancestral secondary cases on the paternal or on the maternal side, which suggests a dominant inheritance. Clinical and epidemiologic features of cases with familial Parkinson's disease showed no peculiarity. The study suggests a strong role of the genetic factors in the etiology of Parkinson's disease.

The clinical and genetic features of 80 patients with Friedreich's disease from 64 families are described. Diagnostic criteria were: no evidence of dominant inheritance, onset by the age of 20 years, progressive unremitting ataxia of limbs and gait, and absence of knee and ankle jerks. Furthermore, at least one of the following accessory signs was present: dysarthria, extensor plantar response and echocardiographic evidence of hypertrophic cardiomyopathy. Two peaks of onset age were evident at 6-9 and 12-15 years. Analysis of intra-family variation of onset age and absence of clustering of cardiomyopathy and diabetes did not suggest genetic heterogeneity. Peripheral nerve impairment was an early finding and showed slight further progression, whereas involvement of the cerebellar and corticospinal pathways appeared later and mainly accounted for the progressive worsening of the disease.

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In order to evaluate the relevance of suicide risk in families affected by Huntington's disease (HD), 2793 subjects registered with the National Huntington's Disease Research Roster were studied. Suicide was the reported cause of death in 205 subjects (7-3%). This group included affected and possibly affected subjects, subjects at 50% and 25% risk, possibly at risk subjects, and normal relatives. In all categories suicide was more frequent than in the general US population. The data suggest that suicide is quite frequent in some families with HD. This increased suicide risk must be carefully considered in planning genetic counselling for predictive testing in HD.