The Congo Red staining showing characteristic birefringence (usually described as apple green) is indicative of amyloid (FA2020 p212). Her findings are characteristic of secondary amyloidosis with serum amyloid A which can cause restrictive cardiomyopathy and nephrotic syndrome and is associated with rheumatoid arthritis.
Amyloid protein composition is misfolded aggregates of beta-pleated sheets.
I just wanted to add that Helix-loop-Helix is an example of a DNA binding motif. https://image.slidesharecdn.com/helix-loop-helix-151109175721-lva1-app6892/95/helixloophelix-helixturnhelix-13-638.jpg?cb=1510121014
High hydroxyproline and multiple disulfide cross-links are for collagen protein.