Sleep disordered breathing in childhood-onset acid maltase deficiency

Objectives: To clarify the feature of sleep disordered breathing (SDB) associated with childhood-onset acid maltase deficiency (AMD): the progressive nature of SDB and the stage of AMD. Study design: We retrospectively studied 4 patients with childhood-onset AMD by analyzing the results of neurological examinations for muscle wasting and muscle strength and the data on venous gas and from a pulmonary function test and nocturnal polysomnography (PSG). Results: Three out of the 4 patients showed muscular symptoms including myalgia, lordoscoliosis, muscle wasting and muscle weakness. They also complained of sleep-related symptoms such as tiredness in the morning and daytime sleepiness. All of them showed SDB by PSG, even in a patient in the earliest stage who exhibited no signs or symptoms of muscle weakness. In 3 patients, noninvasive intermittent positive pressure ventilation during sleep was introduced; and thereafter sleep-related symptoms were resolved and no lower respiratory infection reoccurred. Although their quality of life was improved, no improvement of respiratory function was shown by spirometry over a 2-year follow-up period. Conclusions: SDB seems to be common in childhood-onset AMD, which is not always accompanied by daytime muscular symptoms, especially in mild patients. PSG should be utilized for detecting SDB, which could be one of the earliest signs of respiratory muscle involvement in childhood-onset AMD.