Allelic Diversity in the Serum Amyloid A2 Gene and Amyloid A Amyloidosis in a Breeding Colony of Zebra Finches (Taeniopygia guttata)

Abstract

A high incidence of amyloid A (AA) amyloidosis was observed in the research breeding colony of zebra finches at our institution. Some birds with hepatic AA amyloidosis were asymptomatic for comorbid conditions frequently associated with the development of AA amyloidosis, whereas other birds with comorbid conditions failed to develop AA amyloidosis, suggesting a potential genetic component to the disease. Sequencing the SAA2 gene from 20 birds yielded 18 distinct sequences that coded for 5 isoforms of the protein. Most of the amino acid substitutions are unlikely to affect the protein's structure or function, but 2 changes—R52L and V84M—were predicted to be disruptive. In particular, R52 is highly conserved across vertebrates, with only arginine or lysine found at this position in reported sequences to date. The atypical R52L substitution occurred in 2 otherwise healthy birds with hepatic AA amyloidosis, supporting the idea that this change is pathogenic.

Systemic amyloid A (AA) amyloidosis in the Bengalese finch (<i>Lonchura striata var. domestica</i>)

“…In zebra finch, the degree of amyloid deposition was remarkable in the liver and spleen [ 9 ] and the liver was the most frequently and severely affected organ [ 13 ]. The histological distribution of amyloid deposition is similar to each other in finch species [ 9 , 12 , 13 , 14 ].…”

“…Amyloidosis was reported in three finch species of the order Passeriformes: the Gouldian finch ( Erythrura gouldiae ) [ 18 ], the Australian diamond firetail finch ( Stagonopleura bella ) [ 2 ], and the zebra finch ( Taeniopygia guttata ) [ 9 , 13 , 14 ]. A high incidence of AA amyloidosis was observed in a colony of zebra finches recently, but the actual incidence rate has not been determined [ 13 , 14 ].…”

“…Therefore, a retrospective necropsy survey was conducted to determine the incidence of amyloidosis in dead Bengalese finches in breeding colonies. A histological investigation focused on the three visceral organs that are most frequently affected by avian amyloidosis, i.e., the liver, spleen, and kidneys [ 5 , 6 , 13 , 14 ].…”

“…Five case studies investigated amyloidosis in three finch species (from the order Passeriformes): one study included 4 Gouldian finches from a zoo [ 18 ], one study included an Australian diamond firetail finch from a pet store [ 2 ], another study included a companion zebra finch with amyloidosis [ 9 ], and two studies included a total of 14 zebra finches with AA amyloidosis from a research breeding colony [ 13 , 14 ]. Recently, a high incidence of AA amyloidosis was observed in zebra finches, but the actual incidence rate in colonies has not been determined [ 13 , 14 ].…”

Light chain systemic amyloidosis manifested as liver failure complicated with fatal spontaneous splenic rupture: A case report

“…At present, the etiology or pathogenesis for amyloidosis is still unclear. The study of Shientag Lisa J et al showed that in birds, R52L mutation in the SSA gene might be a genetic factor of hepatic amyloidosis [2] . And all diseases depend on the proportion and interaction of genetics and environment.…”