ABSTRACT
A large GGGGCC-repeat expansion mutation (HREM) in C9orf72 is the most common known cause of ALS and FTD in European populations. Sequence variations immediately downstream of the HREM region have previously been observed and have been suggested to be one reason for difficulties in interpreting RP-PCR data. Our objective was to determine the properties of these sequence variations with regard to prevalence, the range of variation, and effect on disease prognosis. We screened a multi-national cohort (n = 6981) for the HREM and samples with deviant RP-PCR curves were identified. The deviant samples were subsequently sequenced to determine sequence alteration. Our results show that in the USA and European cohorts (n = 6508) 10.7% carried the HREM and 3% had a sequence variant, while no HREM or sequence variants were observed in the Japanese cohort (n = 473). Sequence variations were more common on HREM alleles; however, certain population specific variants were associated with a non-expanded allele.In conclusion, we identified 38 different sequence variants, most located within the first 50 bp downstream of the HREM region. Furthermore, the presence of an HREM was found to be coupled to a lower age of onset and a shorter disease survival, while sequence variation did not have any correlation with these parameters.
Subject(s)
Amyotrophic Lateral Sclerosis/genetics , C9orf72 Protein/genetics , Adolescent , Adult , Age of Onset , Aged , Aged, 80 and over , Amyotrophic Lateral Sclerosis/epidemiology , Base Sequence , Cohort Studies , DNA Repeat Expansion , Female , Frontotemporal Dementia/genetics , Gene Frequency , Genetic Predisposition to Disease , Genetic Variation , Humans , Male , Middle Aged , Polymerase Chain Reaction , Survival Analysis , Young AdultABSTRACT
Botulinum neurotoxin (BoNT) is a second-line treatment of sialorrhoea in ALS (amyotrophic lateral sclerosis) patients. This article is a review of the published literature concerning safety and administration of this treatment to ALS patients. A PubMed search was performed. All original publications on BoNT treatment of sialorrhoea in ALS patients were included in the review. Only a few adverse events were observed concerning treatment with BoNT. The studies performed to date have applied different treatment strategies with different dosages. In conclusion, BoNT treatment for sialorrhoea in ALS patients is safe with few adverse effects. The authors advocate for the implementation of a personalized treatment strategy. Special precautions must be taken when patients do not have the assistance of a ventilator and a feeding tube.
