RESUMO
The autosomal dominant cerebellar ataxias have proved particularly difficult to classify due to the lack of phenotypic concordance both within and between families. Genetic heterogeneity has been established, and disease loci for spinal cerebellar ataxia have been assigned to chromosomes 6 (SCA1), 12 (SCA2) and 14 (Machado Joseph disease (MJD)). Genetic analysis performed on a large Thai kindred with autosomal dominant cerebellar ataxia, in which frontal lobe signs and dementia are commonly observed in affected family members, exclude linkage to the SCA1, SCA2 and MJD loci. This demonstrates that mutation in at least one further locus can cause spinal cerebellar ataxia, indicating the need for caution in the use of markers for predictive testing or prenatal diagnosis these disorders.
Assuntos
Cromossomos Humanos Par 12 , Cromossomos Humanos Par 14 , Cromossomos Humanos Par 6 , Demência/genética , Degenerações Espinocerebelares/genética , Mapeamento Cromossômico , DNA/sangue , DNA/genética , DNA Satélite/genética , Demência/complicações , Feminino , Genes Dominantes , Ligação Genética , Marcadores Genéticos , Humanos , Escore Lod , Masculino , Linhagem , Degenerações Espinocerebelares/complicaçõesRESUMO
To evaluate the efficacy of dexamethasone for treatment of primary supratentorial intracerebral hemorrhage, we studied 93 patients 40 to 80 years old, using a double-blind randomized block design. After the subjects were stratified according to their level of consciousness (Glasgow Coma Scale), those with objectively documented primary supratentorial intracerebral hemorrhage were randomly assigned to either dexamethasone or placebo. For ethical reasons, three interim analyses were planned, to permit early termination of the trial if one study group did better than the other. During the third interim analysis, the death rate at the 21st day was identical in the two groups (dexamethasone vs. placebo, 21 of 46 vs. 21 of 47; chi-square = 0.01, P = 0.93). In contrast, the rate of complications (mostly infections and complications of diabetes) was much higher in the dexamethasone group (chi-square = 10.89, P less than 0.001), leading to early termination of the study. In the light of the absence of a demonstrable beneficial effect and the presence of a significant harmful effect, current practices of using dexamethasone for treatment of primary supratentorial hemorrhage should be reconsidered.
