Anticipation and Phenotypic Heterogeneity in Korean Familial Amyotrophic Lateral Sclerosis with Superoxide Dismutase 1 Gene Mutation

BACKGROUND AND PURPOSE: Different mutations in the Cu/Zn superoxide dismutase 1 (SOD1) gene have been reported in approximately 10% of cases of familial amyotrophic lateral sclerosis (ALS). The aim of this study was to analyze for mutations in the SOD1 gene and clinical characteristics in Korean family of ALS. METHODS: A subpopulation of the family reported here has been described previously. In the present study, we analyzed the SOD1 gene in the proband and his immediate family members, who were not reported on previously. Genomic DNA was isolated from the leukocytes of whole blood samples and the coding region of the SOD1 gene was analyzed by PCR and direct sequencing. RESULTS: The genetic alterations were a GGC-to-GTT transition at codon 10 in exon 1 and [IVS4+15_16insA; IVS4+42delG; IVS4+59_60insT] in intron 4. Patients with these mutations exhibit diverse clinical onset symptoms and acceleration of the age at onset in successive generations, which is called anticipation. CONCLUSIONS: We have described a family with familial ALS that showed autosomal-dominant inheritance and two distinct genetic alterations in Cu/Zn-SOD1. The affected family members had different phenotypes and anticipation.

Denaturing high performance liquid chromatography for detection of point mutation of familial ALS / 第三军医大学学报

Objective To identify the point mutation of Cu/Zn superoxide dismutase(SOD1) gene in an amyotrophic lateral sclerosis(ALS) family and observe the value of denaturing high performance liquid chromatography(DHPLC). Methods DHPLC and DNA sequencing were used to examine SOD1 gene of the ALS family which had not been found mutation by PCR-SSCP. Results DHPLC tests proved double peaks in one member(Ⅲ_1), Which indicated the possibility of mutation in SOD1 exon 4. DNA sequencing revealed that there was a heterozygote,with mutation of GAA to GGA in exon 4, and with a substitution of glutacid by glycine. Conclusion As compared with PCR-SSCP, DHPLC technique has proved to be a rapid and reliable method for screening mutation site in large samples.

Impairment of Neurite Formation in Familial ALS-associated Cu, Zn-Superoxide Dismutase Mutant Cells

BACKGROUND: Mutations in the human Cu, Zn-superoxide dismutase (SOD1) gene have been identified in some cases of familial amyotrophic lateral sclerosis (ALS). Neuronal cells with mutant SOD1 gene promoted cell death during differentiation by dibutyryl cAMP and aphidicolin. The aim of this study is to delineate if there is an impairment of the neural differentiation process in mutant SOD1 cells. METHODS: We studied the motoneuron-neuroblastoma hybrid cells (VSC 4.1) expressing wild-type or mutant SOD1 (G93A) during the differentiation by dibutyryl cAMP and aphidicolin. RESULTS: Mutant SOD1 cell (G93A) showed an impairment in the neurite formation. Western blot analysis revealed that the amount of neurofilament decreased before differentiation. A decrease in the amount of MAP-2 is observed during differentiation. CONCLUSIONS: Our results suggest that the impairment in the neurite formation of mutant SOD1 cell (G93A) is a differentiation failure and is associated with neuronal cell death.

Effect of Familial Amyotrophic Lateral Sclerosis-associated Cu, Zn-superox-ide Dismutase Mutation on Neural Differentiation in Motor Neuronal Cells

BACKGROUND: Mutations in the human Cu, Zn-superoxide dismutase(SOD1) gene have been identified in some cases of familial amyotrophic lateral sclerosis(ALS). The aim of this study is to delineate the effect of the SOD1 mutation on neural differentiation, and to investigate the mechanism of neuronal death. METHODS: We studied motorneuron-neurob-lastoma hybrid cells(VSC 4.1) expressing wild type or mutant SOD1(G93A, A4V) during differentiation by dibutyryl cAMP and aphidicolin. RESULTS: Mutant cells(G93A) revealed a decreased viability compared with the control cells, mainly in the early stage ofdifferentiation. The release of cytochrome c and increased nuclear fragmentation were observed. However, cell death was not protected by nonselective caspase inhibitor(z-VAD-fmk), but by the antioxi-dant( Trolox). CONCLUSIONS: The results suggest that oxidative stress may be the main mechanism of neuronal death, particularly in the early stage of differentiation.