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Prokaeva T, Joshi T, Klimtchuk ES, Gibson VM, Spencer B, Siddiqi O, Nedelkov D, Hu Y, Berk JL, Cuddy SAM, Dasari S, Chiu A, Choate LA, McPhail ED, Cui H, Chen H, Burks EJ, Sanchorawala V, Connors LH. A novel substitution of proline (P32L) destabilises β2-microglobulin inducing hereditary systemic amyloidosis. Amyloid 2022; 29:255-262. [PMID: 35575118 DOI: 10.1080/13506129.2022.2072199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND β2-microglobulin amyloidosis was first described in the 1980s as a protein deposition disease associated with long-term haemodialysis. More recently, two inherited forms resulting from separate point mutations in the β2-microglobulin gene have been identified. In this report, we detail a novel β2M variant, P32L, caused by a unique dinucleotide mutation that is linked to systemic hereditary β2-microglobulin amyloidosis. METHODS Three family members from a Portuguese kinship featured cardiomyopathy, requiring organ transplantation in one case, along with soft tissue involvement; other involvements included gastrointestinal, neuropathic and sicca syndrome. In vitro studies with recombinant P32L, P32G, D76N and wild-type β2-microglobulin were undertaken to compare the biophysical properties of the proteins. RESULTS The P32L variant was caused by the unique heterozygous dinucleotide mutation c.154_155delinsTT. Amyloid disease featured lowered serum β2-microglobulin levels with near equal amounts of circulating P32L and wild-type proteins; amyloid deposits were composed exclusively of P32L variant protein. In vitro studies of P32L demonstrated thermodynamic and chemical instability and enhanced susceptibility to proteolysis with rapid formation of pre-fibrillar oligomeric structures by N- and C-terminally truncated species under physiological conditions. CONCLUSIONS This work provides both clinical and experimental evidence supporting the critical role of P32 residue replacement in β2M amyloid fibrillogenesis.
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Affiliation(s)
- Tatiana Prokaeva
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Tracy Joshi
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Elena S Klimtchuk
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Victoria M Gibson
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Brian Spencer
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Omar Siddiqi
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | | | | | - John L Berk
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA
| | - Sarah A M Cuddy
- Amyloidosis Program, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Surendra Dasari
- Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA
| | - April Chiu
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Lauren A Choate
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Ellen D McPhail
- Department of Laboratory of Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Haili Cui
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA.,Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Hui Chen
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Eric J Burks
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
| | | | - Lawreen H Connors
- Amyloidosis Center, Boston University School of Medicine, Boston, MA, USA.,Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
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