Action myoclonus–renal failure syndrome: A cause for worsening tremor in young adults

Abstract

Action myoclonus–renal failure syndrome (AMRF) is an autosomal recessive disorder first described in 4 French Canadian patients, followed by a recent description of 15 cases from various countries.1,2 The condition independently affects the kidney, with focal glomerulosclerosis causing renal failure and the brain causing progressive myoclonus epilepsy (PME) or progressive myoclonic ataxia (PMA).3,4 Tremor is often an early feature. The diagnosis of tremor and myoclonus in patients with severe renal disease is challenging. Here we highlight the evolution of tremor in this syndrome in two new cases and emphasize problems in early diagnosis. ### Case 1. Case 1 is an Australian man of English ancestry with unrelated parents (figure). He was well until age 20 when end-stage renal failure developed, after a 3-month history of anorexia, nausea, and lethargy. Renal ultrasound demonstrated small kidneys; the etiology of renal failure was not established and renal biopsy not performed. He was treated with dialysis. Figure. Pedigrees of the two subjects (filled symbols) with action …