Amyloid : the international journal of experimental and clinical investigation : the official journal of the International Society of Amyloidosis
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Clinical Trial
Safety and efficacy of a TTR specific antisense oligonucleotide in patients with transthyretin amyloid cardiomyopathy.
Cardiomyopathy is a major cause of death in both the hereditary form of transthyretin (TTR) amyloidosis and the sporadic late-age-onset transthyretin amyloidosis (ATTR wild-type (ATTRwt)). Clinically disease progression from time of diagnosis to death is usually quoted as 5- to 15-years. In prior studies, significant progression of cardiac parameters in patients with moderate to severe cardiomyopathy has been noted within a 12-month time span. ⋯ ASO treatment of patients with moderate to advanced ATTR cardiomyopathy shows indication of stabilization of disease progression and may therefore contribute to enhanced life expectancy.
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Proteomics is becoming the de facto gold standard for identifying amyloid proteins and is now used routinely in a number of centres. The technique is compound class independent and offers the added ability to identify variant and modified proteins. We re-examined proteomics results from a number of formalin-fixed paraffin-embedded amyloid samples, which were positive for transthyretin (TTR) by immunohistochemistry and proteomics, using the UniProt human protein database modified to include TTR variants. ⋯ These processing-derived modifications are not present in fresh cardiac tissue, non-fixed fat nor serum and do not materially affect the identification of amyloid proteins. They could result in the incorrect assignment of a variant, and this may have consequences for the immediate family who will require genetic counselling and potentially early clinical intervention. As proteomics becomes a routine clinical test for amyloidosis, it becomes important to be aware of potentially confounding issues such as formalin-mediated lysine methylation, and how these may influence diagnosis and possibly treatment.