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Recent clinical, experimental and epidemiological studies report that ALS is thought possibly due to a multi-stage process, arising from a combination of genetic susceptibility and environmental factors, which alone or superimposed, perhaps on genetic polymorphism yet to be identified, may contribute to the incidence rate of sporadic ALS. In particular, a large amount of evidence suggests that mercury is toxic to motor neurons and may be a risk factor for ALS, playing a part in its pathogenesis. In fact, there have been case reports of ALS or ALS-like symptoms associated with mercury exposure, thus raising the possibility that mercury could be one of the non-genetic factors of the multistep process that is thought to underlie ALS. In order to give recent elucidations on the putative relationship between mercury exposure and ALS, we reviewed all the papers reported in the literature and published on Pubmed from 2006 to 2022. Despite a number of pathogenetic mechanisms that have been linked to mercury, evidence linking exposure to mercury to ALS is not consistent and discordant and, based on the evaluation of the articles, which emerged from our analysis that to date no convincing correlation between mercury and ALS has been established and no conclusive evidence has been enlightened suggesting increased mercury exposure is associated with ALS. more...

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebrovascular disease whose key features are recurrent transient ischemic attacks (TIA), strokes, migraine with aura, vascular dementia, and diffuse white matter abnormalities detectable through neuroimaging. The disease results from mutations in the NOTCH3 gene, encoding a transmembrane receptor involved in cellular signaling and fate during embryonic development. Genetic testing is the gold standard for diagnosing this condition, but the syndrome can be suspected clinically based on family history and characteristic findings of white matter changes. Nevertheless, different individual symptom types, onset, and disease severity, even among individuals in the same family, have been increasingly recognized. The molecular mechanisms by which NOTCH3 mutations lead to vascular degeneration remain unclear. Most CADASIL-associated mutations result in either a gain or loss of cysteine residue in one of the 34 EGF-like repeats in the extracellular domain of the Notch3 protein, thus sparing the number of cysteine residues. More than 200 different mutations in the NOTCH3 gene have been reported in CADASIL patients, of which 95% are missense point mutations. Although it has been suggested that some mutations may be associated with a milder or more severe phenotype, so far no clear genotype-phenotype correlation has been found. To date, no disease-modifying treatment is available for this condition. more...

Amyotrophic Lateral Sclerosis and CHARGE syndrome are complex neurological disorders, which never occurred together in the same family and, to date, no putative correlation between them has been described on PubMed Central. Due to our aim was to evaluate the presence of different genetic variants involved in these pathologies, we reported a clinical and genetic description of two sisters affected by these two different disorders. In the CHARGE patient, molecular analysis of the CHD7 gene revealed the c.8016G >A de novo variant in exon 37. The ALS patient had been screened negative for mutations in SOD1, TARDBP, FUS/TLS, C9orf72 and KIF5A genes. Anyway, targeted next generation sequencing analysis identified known and unknown genetic variations in 39 ALS-related genes: a total of 380 variants were reported, of which 194 in the ALS patient and 186 in the CHARGE patient. To date, although the results suggest that the occurrence of the two syndromes in the same family is co-incidental rather than based on a causative genetic variant, we could hypothesize that other factors might act as modulators in the pathogenesis of these different phenotypes. Electronic supplementary material The online version of this article (10.1007/s13760-018-1029-2) contains supplementary material, which is available to authorized users. more...