Introduction. Pompe disease is an inherited metabolic myopathy due to lysosomal glycogen deposition in the absence or reduction of acid maltase enzyme activity. The worldwide prevalence of the disease ranges from 1:40,000 to 1:200,000 and it affects children and adults. Objective. This study aims to report the case of a patient diagnosed with the late form of Pompe disease. Case Report. A 44-year-old female patient had the onset of symptoms of Pompe disease at the age of 14, presenting difficulty in walking and frequent falls. The disease was diagnosed three years later. At the age of 44 and after using enzyme therapy replacement (TER) for 12 years, the clinical condition evolved into quadriplegia and involvement of the respiratory and orofacial muscles, despite the use of enzyme replacement therapy for 12 years. Conclusion. Despite the use of ERT and the care provided by a multidisciplinary team, the patient evolved with an unfavorable clinical outcome. Therefore, early diagnosis, level of enzyme activity, and response to treatment with enzyme replacement are essential for the disease prognosis.