Congenital Fiber Type Disproportion (CFTD) is a rare genetic muscle disorder characterized by an abnormal proportion of muscle fiber types within skeletal muscles. It is present at birth (congenital) and affects the size and metabolism of different types of muscle fibers.
In individuals with CFTD, there is an imbalance in the size and distribution of type I and type II muscle fibers. Type I fibers, also known as slow-twitch fibers, are responsible for endurance activities, while type II fibers, or fast-twitch fibers, enable quick and powerful movements. This disproportion results in various muscle-related symptoms.
Common signs of CFTD often involve muscle weakness, hypotonia (low muscle tone), delayed motor skills, and a decreased ability to perform physical activities compared to typically developing individuals of the same age. Additional symptoms may include joint stiffness, contractures, and scoliosis. In some cases, the respiratory muscles may also be affected, leading to breathing difficulties.
CFTD is caused by mutations in specific genes that play a crucial role in the development and function of muscle fibers. It can be inherited in an autosomal dominant or autosomal recessive manner, depending on the responsible gene and its pattern of inheritance.
Diagnosis of CFTD typically involves a thorough clinical evaluation, including physical examination, medical history, and muscle biopsy. Genetic testing may also be employed to identify the specific gene mutation.
While there is currently no cure for CFTD, treatment approaches aim to manage symptoms and improve quality of life. These may include physical therapy, assistive devices to aid mobility, respiratory support if needed, and other supportive measures.
