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More than 140 different mutations have been reported in the Cu/Zn superoxide dismutase-1 ( SOD1) gene in patients with amyotrophic lateral sclerosis (ALS), some occurring as founder mutations. Occasionally, specific mutations are associated with a particular phenotype. We evaluated a possible genotype-phenotype correlation and looked for a founder effect in nine patients from six unrelated families with ALS, all carrying the G41S mutation, originating from north-west Tuscany in central Italy. Mutational analysis of the SOD1 gene was carried out by direct sequencing. A haplotype study was carried out using eight polymorphic markers flanking the SOD1 gene. The clinical pattern of the nine familial ALS (FALS) patients was characterized by spinal onset with early upper and lower motor neuron involvement, appearance of bulbar signs within one year, and death a few months later. Mean age at onset was 49.3 years and mean duration of disease was 0.9 years. Genotyping revealed a common haplotype for the G41S allele. We provide the first evidence that the G41S mutation in Italy originates from a common founder. In addition, our findings strengthen the data reported previously and indicate that the G41S mutation is consistently associated with a uniform and dramatic, fast-progressing phenotype. [ABSTRACT FROM AUTHOR]

Among the 140 Cu/Zn superoxide dismutase-1 (SOD1) gene mutations associated with ALS, only D90A, the most prevalent mutation in Europe, has been clearly shown to cause recessive and dominant ALS. Here we first describe two, apparently sporadic, Italian ALS patients heterozygous for the D90A mutation. One patient experienced early sensory involvement, confirmed by nerve biopsy. We review sensory symptoms in SOD1 ALS and discuss its possible origin in D90A heterozygous patients. [ABSTRACT FROM AUTHOR]

This review deals with the state of the art in knowledge about molecular diagnostics in mitochondrial diseases. A considerable development over the last years of several lines of biological, biochemical and biophysical investigation techniques has enormously enlarged the chance to obtain significant information by their application in the study of mitochondrial diseases in both in vivo and in vitro clinical applied research. The nosography of mitochondrial diseases is, therefore, day by day enriched by reports of new acquisitions that merge with the innovative contribution that novel laboratory and clinical investigative technologies add to the knowledge of the physiopathology and management of these complex diseases. Apart from the molecular genetic characterization of mitochondrial diseases, different experimental laboratory approaches have contributed, from a molecular point of view, to add new insights in this field of medicine. The strategies of these investigations can be targeted to detect and evaluate the significance of molecules that can play a relevant role in the determination of clinical phenotypes, making it possible to better understand several still unexplained mechanisms of cell damage. [ABSTRACT FROM AUTHOR]

The Aspartate-90-Alanine (D90A) mutation on SOD-1 gene, the only known change causing recessive familial amyotrophic lateral sclerosis (FALS), is associated with a uniform phenotype characterized by slowly ascending paresis and long survival. Originally reported in Scandinavian cases, it has also been detected in patients from other countries. A common haplotype, probably of Scandinavian origin, has been demonstrated in D90A recessive pedigrees. In this study we screened the SOD-1 gene for the D90A mutation in 56 Italian patients from north-west Tuscany with sporadic ALS in order to evaluate the occurrence of this mutation and its genotype-phenotype correlation in Italy. We found the homozygous D90A mutation in one patient (1.8%), harboring the classical phenotype related to this mutation. No other mutations were detected in any of the five SOD-1 exons in our group. Our results confirm that recessive D90A mutation is present in Italy and it is associated with the phenotype already described A screening for that mutation, easily made by RFLP, should be made in sporadic ALS patients, especially where clinical investigation indicates its presence. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the possible contribution of three common functional polymorphisms in the DNA repair protein X-ray repair cross-complementing group 1 (XRCC1), namely Arg194Trp (rs1799782), Arg280His (rs25489) and Arg399Gln (rs25487), to sporadic amyotrophic lateral sclerosis (SALS). We genotyped 206 Italian SALS patients and 203 matched controls for XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphisms by means of PCR/RFLP technique, searching for association between any of the studied polymorphisms and disease risk, age and site of onset. We observed a statistically significant difference in XRCC1 Gln399 allele frequencies between SALS cases and controls (0.39/0.28; p=0.001). The present study suggests that the XRCC1 Arg399Gln polymorphism might contribute to SALS risk. [ABSTRACT FROM AUTHOR]

Background. Disulfiram may cause a peripheral neuropathy that is considered dose- and duration-of-exposure-related. Axonal degeneration has been described as a pathological hallmark of disulfiram toxicity, but experiments have reported a primary toxic effect of the molecule on Schwann cells and myelin. Case Reports. Case 1: At the end of two months of treatment with disulfiram 250 mg/day, a 31-year-old woman complained of weakness in distal segments of the lower limbs associated with burning dysesthesias, numbness and pain in the soles of the feet and the legs below the knees; bilateral walking steppage, reduction in foot strength, absence of ankle jerk and knee tendon reflexes, and tactile stocking pin-pick and vibratory sensory impairment in the lower limbs below the knee. Disulfiram was discontinued and she recovered partially over three months. Case 2: After one month of treatment with disulfiram 1600 mg/day, a 27-year-old man reported walking impairment, distal lower limb weakness and paresthesias. He had unsteady gait with bilateral steppage and foot drop, absence of ankle jerks and overall sensation impairment below the knee. Disulfiram was discontinued and nine months later there was almost complete recovery of motor deficits, only minor motor weakness in distal leg muscles, and no dysesthesia, sensation deficits or areflexia. In both of them clinical and neurophysiological patterns were indicative of a distal axonopathy. Discussion. The mechanisms by which disulfiram cause injury in human nerves are unclear, though may involve carbon disulfide. The discrepancy between experimental and clinical observations is still unexplained. Conclusion. We report two cases of disulfiram axonal toxicity and the partial response following discontinuation of the drug. [ABSTRACT FROM AUTHOR]