De Novo Fibrinogen A Alpha Chain Amyloidosis in a Kidney Transplant Patient: Case Report and Literature Review

RATIONALE: De Novo transplant amyloidosis denotes the condition when a patient develops amyloidosis after transplantation but had not been diagnosed with the disease prior to transplantation. The incidence of de novo amyloidosis in kidney transplants is rare, but few published case reports have described the occurrence of de novo Amyloid A protein (AA) and Light Chain (AL) amyloidosis. However, de novo hereditary fibrinogen A alpha chain (AFib) has not been previously reported. PATIENT PRESENTATION: We present a 72-year-old man, a kidney transplant recipient, who developed progressive rise in his creatinine about 3 years after transplantation. He has long-standing diabetes mellitus type 2, obesity, and hypertension, so he did not have a kidney biopsy of his native kidneys prior to transplantation. DIAGNOSIS: A kidney transplant biopsy was done that showed amyloidosis. Mass spectrophotometry confirmed it as AFib amyloidosis. Genetic testing of the patient revealed that he has fibrinogen A alpha gene (FGA) point mutation with a p.E545V variant. INTERVENTIONS: Cardiac evaluation showed normal transthoracic echocardiogram. Cardiac magnetic resonance imaging (MRI) showed no involvement by amyloidosis. A peripheral nerve biopsy showed diabetic neuropathy. Thus, the kidney was the only organ involved by the disease. The kidney transplant was managed conservatively with blood pressure and diabetes control in addition to his usual immunosuppression regimen which was not altered. He is being treated with diuretics, angiotensin receptor inhibitors, and sodium glucose transport 2 inhibitors. OUTCOMES: Kidney transplant function exhibited only slow progression over 18 months since the diagnosis was confirmed. This slow progression is likely because the p.E545V point mutation variant is less aggressive than other gene deletion mutations and because our patient was judged to have been diagnosed early in the course of his disease. TEACHING POINTS: In this case report, we illustrate the findings and testing that confirmed the diagnosis of AFib amyloidosis. We summarize the clinical aspects, outcomes of the disease, and treatment options. We believe this case report is interesting because it is the first reported case of AFib amyloidosis in a kidney transplant recipient who was not known to have the disease prior to kidney transplantation.