Hereditary transthyretin amyloidosis presenting with spontaneous periorbital purpura: a case report

Background Amyloidosis is a systemic disorder of abnormal protein folding and deposition resulting in a range of symptoms including neuropathy, heart failure, renal disease, and dermatologic findings. The two most common types of amyloidosis that affect the heart are transthyretin (ATTR) amyloidosis and light chain (AL) amyloidosis, which vary in clinical presentation. Skin findings such as periorbital purpura are considered more specific for AL amyloidosis. However, there are rare cases of ATTR amyloidosis causing the same dermatologic findings. Case Summary A 69-year-old female presented for evaluation of amyloidosis after cardiac imaging done at the time of a recent atrial fibrillation ablation showed signs of infiltrative disease. On examination, she had periorbital purpura which she reportedly had for years without receiving a diagnosis, as well as macroglossia with teeth indentation. These exam findings, in addition to her transthoracic echocardiogram showing apical sparing, are typically considered characteristic of AL amyloidosis. Subsequent workup revealed the presence of hereditary ATTR (hATTR) amyloidosis with a heterozygous pathogenic variant in the TTR gene producing the p.Thr80Ala mutation. Conclusion Spontaneous periorbital purpura is thought to be pathognomonic for AL amyloidosis. However, we describe a case of hereditary ATTR amyloidosis with the Thr80Ala TTR genetic variant presenting initially with periorbital purpura, the first case documented in the literature to our knowledge.