Centronuclear Myopathy (CNM) is a rare genetic muscle disorder that primarily affects skeletal muscles, which are responsible for voluntary movements. It is characterized by muscle weakness and abnormal positioning of the nuclei within the muscle cells, hence the name "centronuclear."
Symptoms:
1. Muscle Weakness: One of the hallmark symptoms of CNM is muscle weakness, which can vary in severity. It typically affects the muscles closest to the center of the body, such as the neck, shoulders, hips, and thighs. Weakness may also be present in the facial muscles, causing difficulties with swallowing, speaking, and facial expressions.
2. Delayed Motor Development: Infants with CNM often experience delayed motor development. They may have difficulty achieving milestones such as sitting, crawling, and walking. The weakness in the muscles can make it challenging for them to perform these movements.
3. Respiratory Problems: Some individuals with CNM may develop respiratory complications due to weakness in the muscles involved in breathing. This can lead to difficulties with breathing, especially during sleep or physical exertion. In severe cases, respiratory support may be required.
4. Joint Contractures: Joint contractures, where the joints become fixed in a bent or flexed position, can occur in individuals with CNM. This can affect mobility and range of motion, making it difficult to perform certain movements.
5. Muscle Wasting: Over time, individuals with CNM may experience muscle wasting or atrophy. This can result in a decrease in muscle size and bulk, further contributing to weakness and functional limitations.
6. Ptosis: Ptosis refers to drooping of the upper eyelids. It is a common feature in CNM and can affect one or both eyes. Ptosis can impair vision and may require surgical intervention in some cases.
7. Swallowing Difficulties: Weakness in the muscles involved in swallowing can lead to difficulties in swallowing food and liquids. This can increase the risk of choking and aspiration.
8. Fatigue: Many individuals with CNM experience fatigue, which can be both physical and mental. The constant effort required to compensate for muscle weakness can be draining and impact daily activities.
9. Cardiac Involvement: In rare cases, CNM may be associated with cardiac abnormalities, such as arrhythmias or cardiomyopathy. Regular cardiac evaluations are recommended for individuals with CNM to monitor and manage any potential cardiac issues.
It is important to note that the severity and specific symptoms of CNM can vary widely among affected individuals. Some individuals may have mild symptoms and lead relatively normal lives, while others may experience significant disability and require assistance with daily activities.