RÉSUMÉ
Cystinosis is a rare metabolic disorder characterized by lysosomal cystine accumulation leading to multi-organ damage, with kidneys being clinically first affected. Longer survival of cystinosis patients due to successful renal replacement therapy, revealed previously unknown extra-renal symptoms of cystinosis, generally appearing after the first decade. Respiratory insufficiency caused by overall respiratory muscle myopathy is a severely invalidating and sometimes a life-threatening complication of cystinosis. We report a successful treatment of hypoventilation, due to diaphragm myopathy in a cystinosis patient, by nocturnal non-invasive positive pressure ventilation (NIPPV). After initiation of NIPPV the clinical condition of the patient improved and blood-gasses normalized, indicating that this treatment modality should be considered in cystinosis patients with severe respiratory insufficiency.