Cardiac amyloidosis, a monoclonal gammopathy and a potentially misleading mutation.

BACKGROUND: A 46-year-old Afro-Caribbean man presented with progressive dyspnea and recurrent syncope. Clinical examination revealed evidence of biventricular failure.

INVESTIGATIONS: Electrocardiography, echocardiography, cardiac biopsy, measurement of serum levels of free light chain, scintigraphy with radiolabeled serum amyloid P component, transthyretin gene sequencing and immunohistochemistry.

DIAGNOSIS: Cardiac acquired monoclonal immunoglobulin-light-chain amyloidosis with the incidental presence of the amyloidogenic transthyretin Val122Ile mutation.

MANAGEMENT: The patient was referred for consideration of urgent cardiac transplantation and subsequent autologous stem cell transplantation. Unfortunately, he died suddenly within a few weeks of referral.