Many people first experience muscle weakness in the legs and hips, often together with breathing difficulties. However, the age at which these symptoms first appear can vary widely, as can the severity of the symptoms and the rate at which they worsen. Also, it is important to note that the heart problems typically seen in infants with Pompe disease are rare among older children and adults with the condition.
The earliest signs of Pompe disease in children and adults depend on the age at which they first appear. For example, younger children may not learn to walk, run or jump as quickly as expected, or they may lose movement abilities that they once had. Children with Pompe disease may also trip or fall more frequently than usual as they move around. In adults with Pompe disease, the first sign of the condition may be difficulty rising from a seated position. Breathing-related symptoms often appear after movement difficulties are seen, but they can occur first. Breathing difficulties often first appear as shortness of breath after physical effort, or sometimes as morning headaches and daytime sleepiness (as a result of problems breathing during the night).
Children and adults with Pompe disease tend to worsen far more gradually than infants with the condition. Some people experience only minor disability, whilst others gradually lose the ability to walk or breathe on their own and eventually require additional support. Thus, the time it takes for Pompe disease to worsen varies a great deal. Some people with the condition are able to adapt and live relatively normal lives, whilst others are severely affected.