Mortality in Friedreich ataxia.

BACKGROUND: Although cardiac dysfunction is widely accepted as the most common cause of mortality in Friedreich ataxia (FRDA), no studies have evaluated this since the advent of specific clinical and genetic diagnostic criteria.

METHODS: We performed a retrospective study of FRDA patients to determine cause of death followed by a case-control analysis comparing characteristics of deceased patients with living, age- and sex-matched FRDA controls.

RESULTS: Causes of death were cardiac dysfunction (59%), probable cardiac dysfunction (3.3%), non-cardiac (27.9%) or unknown (9.8%). Compared to non-cardiac deaths, cardiac deaths occurred earlier in the disease course (median 29 vs. 17years respectively). Congestive heart failure and arrhythmia were common causes of cardiac-related death. Compared to living, matched FRDA controls, deceased patients had longer triplet repeat lengths and higher rates of arrhythmia and dilated cardiomyopathy. The presence of hypertrophic cardiomyopathy did not differ between deceased and living patients.

CONCLUSION: Cardiac dysfunction was the most frequent cause of death (59%), most commonly from congestive heart failure or arrhythmia. Arrhythmia and dilated cardiomyopathy were significantly more common in deceased patients compared to matched FRDA controls, while in contrast, the presence of cardiac hypertrophy did not differ. More research is needed to establish the clinical significance of hypertrophy in FRDA.