Mechanisms of unexpected death and autopsy findings in Friedreich ataxia

A 36-year-old woman with a clinical history of Friedreich ataxia and hypertrophic cardiomyopathy was found unexpectedly dead at her home. The heart showed asymmetric left ventricular hypertrophy, with an interventricular septal thickness of 20-25mm (the remainder of the left ventricular wall measured 15mm). Histologically, both ventricles had irregular areas of marked myocyte hypertrophy with associated interstitial fibrosis and focal myofibre disarray. There was neuronal loss within the dentate nucleus of the cerebellum, with vacuolation and axonal loss in the dorsal columns and spinocerebellar tracts of the upper cervical spinal cord. Death was due to hypertrophic cardiomyopathy complicating Friedreich ataxia. Other causes of death in this condition include embolic stroke, cerebral haemorrhage, aspiration pneumonia, renal failure, diabetic ketoacidosis, myocardial infarction, generalised inanition and trauma. Sudden death due to cardiac disease, resulting in presentation for medicolegal autopsy, may be the presenting feature at all ages, including childhood.