title: Hereditary Lysozyme Amyloidosis Variant p.Leu102Ser Associates with Unique Phenotype.
abstract: Lysozyme amyloidosis (ALys) is a rare form of hereditary amyloidosis that typically manifests with renal impairment, gastrointestinal (GI) symptoms, and sicca syndrome, whereas cardiac involvement is exceedingly rare and neuropathy has not been reported. Here, we describe a 40-year-old man with renal impairment, cardiac and GI symptoms, and peripheral neuropathy. Renal biopsy specimen analysis revealed amyloidosis with extensive involvement of glomeruli, vessels, and medulla. Amyloid was also detected in the GI tract. Echocardiographic and electrocardiographic findings were consistent with cardiac involvement. Proteomic analysis of Congo red-positive renal and GI amyloid deposits detected abundant lysozyme C protein. DNA sequencing of the lysozyme gene in the patient and his mother detected a heterozygous c.305T>C alteration in exon 3, which causes a leucine to serine substitution at codon 102 (Human Genome Variation Society nomenclature: p.Leu102Ser; legacy designation: L84S). We also detected the mutant peptide in the proband's renal and GI amyloid deposits. PolyPhen analysis predicted that the mutation damages the encoded protein. Molecular dynamics simulations suggested that the pathogenesis of ALys p.Leu102Ser is mediated by shifting the position of the central β-hairpin coordinated with an antiparallel motion of the C-terminal helix, which may alter the native-state structural ensemble of the molecule, leading to aggregation-prone intermediates.
authors.affiliation: Departments of Laboratory Medicine and Pathology.
authors.forename: Samih H
authors.initials: SH
authors.lastname: Nasr
authors.affiliation: Health Sciences Research, and.
authors.forename: Surendra
authors.initials: S
authors.lastname: Dasari
authors.affiliation: Departments of Laboratory Medicine and Pathology.
authors.forename: John R
authors.initials: JR
authors.lastname: Mills
authors.affiliation: Departments of Laboratory Medicine and Pathology.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Theis
authors.affiliation: Health Sciences Research, and.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Zimmermann
authors.affiliation: Department of Internal Medicine, Mayo Clinic in Arizona, Phoenix, Arizona.
authors.forename: Rafael
authors.initials: R
authors.lastname: Fonseca
authors.affiliation: Departments of Laboratory Medicine and Pathology.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Vrana
authors.affiliation: Department of Internal Medicine, Mayo Clinic in Arizona, Phoenix, Arizona.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Lester
authors.affiliation: Department of Clinical Genomics, Mayo Clinic in Arizona, Scottsdale, Arizona.
authors.forename: Brooke M
authors.initials: BM
authors.lastname: McLaughlin
authors.affiliation: Department of Cardiology, Sharp Rees-Stealy Medical Group, San Diego, California; and.
authors.forename: Robert
authors.initials: R
authors.lastname: Gillespie
authors.affiliation: Departments of Laboratory Medicine and Pathology.
authors.forename: W Edward
authors.initials: WE
authors.lastname: Highsmith
authors.affiliation: Department of Pathology, Sharp Memorial Hospital, San Diego, California.
authors.forename: John J
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Departments of Laboratory Medicine and Pathology.|Medicine, Mayo Clinic, Rochester, Minnesota.
authors.forename: Angela
authors.initials: A
authors.lastname: Dispenzieri
authors.affiliation: Departments of Laboratory Medicine and Pathology, Kurtin.Paul@mayo.edu.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Kurtin
mesh_terms: D000328:Adult; D028226:Amyloidosis, Familial / Q000201:enzymology / Q000235:genetics*; D006801:Humans; D008297:Male; D009113:Muramidase / Q000378:metabolism; D010375:Pedigree; D010641:Phenotype
chemical_list: D009113:Muramidase
keywords: amyloidosis; hereditary amyloid; lysozyme; malfolding proteins