Novel amyloidogenic “private” Aα-chain frameshift variant in a French family. (A) The family pedigree of the AFib-kindred with familial segregation of the Phe521Leufs variant because of a single thymine deletion at Phe521. Squares denote male family members; circles, female family members; and solid symbols, affected family members. (B) Partial sequence of FGA exon 5 from II.2, indicating heterozygosity for deletion of a single thymine leading to superimposed sequences after codon 521. (C) Congo red deposits in the glomeruli of renal specimens from II.2 (original magnification ×400). (D) The amyloid fibrils found in the mesangium and under the glomerular basement membrane, appearing as straight unbranched fibrils with 10 nm diameter by electron microscopy (original magnification ×1400). The asterisk indicates the fibrils. (E) Positive staining with the specific Aα-chain antibody raised against the C-terminal Aα-chain mutant sequence (black arrow).