 Eligible Fabry patients are investigated by completion of ESS and one ambulatory overnight respiratory polygraphy oRP. An ESS over 11 is defined as excessive daytime sleepinessEDS. An apnoeahypopnoea index AHI over 5 per minute is defined as sleep apnoea. Distinction of obstructive sleep apnoea OSA and central sleep apnoea CSA is performed by analysis of oRP. Medical history, clinical and laboratory data, and current treatment will be extracted from patient files and the retrospective cohort study, respectively. 