In other species: chicken , bats , white-tufted-ear marmoset , dog , red fox , domestic cat , Sumatran tiger , bottlenosed dolphin , pig , taurine cattle , goat , sheep , cheetah , northern tree shrew , Japanese squirrel , island gray fox

Categories: Homeostasis / metabolism phene

Mendelian trait/disorder: unknown

Disease-related: yes

Cross-species summary: “Amyloid is the term for a misfolded protein that accumulates as insoluble fibrils in various organ and tissue sites to result in a clinical syndrome known as amyloidosis. The chemical diversity of amyloid and amyloidosis has been evident since the mid-1970s and the number of known human amyloid proteins has steadily increased from two at that time to 36 at Amyloid deposition, either hereditary or acquired, is seldom benign and, when clinical symptoms appear, they are frequently life-threatening. The best way to distinguish the different forms of amyloid is by chemical characterization. (Immuno-)histochemical typing of amyloid is readily available … . [A] second descriptor is whether the patient’s amyloid is limited (localized) or throughout the whole body (systemic). Each amyloid syndrome should be named according to the Nomenclature Guidelines of the ISA. Most of the distinct amyloidosis syndromes are named after the fibril forming protein, e.g. AL (amyloid derived from immunoglobulin light chain) amyloidosis (localized or systemic), AA amyloidosis (amyloid derived from SAA – serum amyloid A protein) … .” (International Society of Amyloidosis) Sipe et al., 2016: “The terms “hereditary amyloidosis” and “familial amyloidosis” refer to different entities. The term “hereditary amyloidosis” should be used when there is a mutation in the fibril protein gene itself, e.g. ATTR, ALys or AFib. The term “familial amyloidosis” should be used when the syndrome occurs in a familial setting due to mutations in genes expressing non-amyloid proteins, e.g. AA amyloidosis.”

Molecular basis: By sequencing a comparative candidate gene (SAA2), Shientag et al. (2019) identified an "R52L substitution [that] occurred in 2 otherwise healthy birds with hepatic AA amyloidosis, supporting the idea that this change is pathogenic".