Cardiac Positron-Emission Tomography Images With an Amyloid-Specific Tracer in Familial Transthyretin-Related Systemic Amyloidosis

We report the case of a 32-year-old man who had suffered from orthostatic syncope and body weight loss since he was 27 years old. As years passed by, he also showed muscle weakness and abnormal sensations in both legs, hyporeflexia in 4 limbs, and autonomic failure (impotence, urinary and fecal incontinence, and edema in lower limbs) suggesting the presence of peripheral somatic and autonomic polyneuropathy. His mother, mother's father, and mother's paternal aunt also had similar symptoms. Both the sensory nerve action potential and the sensory nerve conduction velocity of his right sural nerve were low (1.26 μV and 47.2 m/s, respectively), and the motor nerve conduction velocity of his right tibial nerve was 41.1 m/s (normal >45 m/s). A DNA test on the man disclosed a missense mutation in the transthyretin gene (Ser50Arg), which is relatively rare …