Frequencies and geographic distributions of genetic mutations in transthyretin- and non-transthyretin-related familial amyloidosis.

Inherited forms of amyloidosis are rare; of these, transthyretin-related (ATTR) is the most common, but non-ATTR has been described as well. We studied a large case series of ATTR and a small series of non-ATTR to better determine the mutation frequencies and geographic distributions of these inherited forms of amyloidosis in the United States. We performed a retrospective cross-sectional study of 284 ATTR and non-ATTR patients seen at Mayo Clinic in Rochester, Minnesota, from 1 January 1970 through 29 January 2013. Mutations were identified by DNA sequencing, restriction fragment length polymorphism, or mass spectroscopy. The genetic testing method was unknown for several patients, but a small proportion were identified by family history or by classical clinical presentation associated with a specific mutation. The most common ATTR mutations were Thr60Ala (24%), Val30Met (15%), Val122Ile (10%), and Ser77Tyr (5%). Non-ATTR mutations included gelsolin (n = 3), apolipoprotein A-I (n = 6), apolipoprotein A-II (n = 1), fibrinogen A-α (n = 9), and lysozyme (n = 1). Although rare, ATTR and, to a lesser extent, non-ATTR are prevalent in the United States and should be considered for patients presenting in the appropriate clinical context.

Cerebral infarction in POEMS syndrome: incidence, risk factors, and imaging characteristics.

OBJECTIVES: To determine the risk factors and incidence of cerebral infarction associated with POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome. METHODS: The Mayo Clinic dysproteinemia database was queried to identify patients with coded diagnosis of POEMS syndrome. Patients with cerebral infarction, occurring after the onset of POEMS-related symptoms, were selected. A retrospective observational study design was used to evaluate potential predictors of stroke in patients with POEMS syndrome. RESULTS: A total of 9 patients (10%; 95% confidence interval 5.4-17.9) with cerebral infarction were identified (2 women, 22%). Traditional stroke risk factors were not significantly different between the stroke and nonstroke subgroups, but hematologic abnormalities such as elevated platelet count and bone marrow plasmacytosis differed between the 2 groups. Cerebral infarction occurrence after successful treatment of the underlying condition was not observed. CT and MRI data demonstrated a wide spectrum of infarct topography in these patients. Common stroke etiologies comprised suspected vascular structural abnormalities leading to vessel dissection and stenosis, in addition to embolism from a proximal source. CONCLUSIONS: The 5-year risk of cerebral infarction in patients with POEMS syndrome is 13.4%. Evidence of plasma cell proliferation within the bone marrow and elevated serum platelet count led to increased risk of cerebral infarction in this population. We conclude that known modifiable stroke risk factors should be aggressively managed. Treatment of thrombocytosis should be considered in patients without a contraindication. Treatment of the syndrome may be the best approach to decreasing risk of cerebral infarction in these patients.