Action myoclonus-renal failure syndrome: the definitive clinico-pathological description

Abstract

The causes of myoclonus are protean and often obscure; none more obscure than the action myoclonus–renal failure (AMRF) syndrome reported in four French Canadian patients from the province of Quebec by Andermann et al . in 1986. In their current paper, Andermann and colleagues transform this condition from a local rarity to one of global significance, identified in families from Canada, the USA, Cuba, Europe and Australia (Badhwar et al ., 2004). Patients in their series presented in the second and third decades of life with renal, neurological or combined features. Tremor was usually followed by the development of progressively disabling myoclonus on voluntary movement, coupled with cerebellar signs, infrequent generalized seizures, but preserved cognitive function. Renal disease presented as proteinuria and progressed to renal failure. Renal biopsy revealed collapsing glomerulopathy, a severe variant of focal segmental glomerulosclerosis that is more commonly seen in the setting of human immunodeficiency virus infection. …