Facioscapulohumeral muscular dystrophy: Year of the Zebra

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Facioscapulohumeral muscular dystrophy, or FSHD for short, is a genetic neuromuscular disorder that causes weakness in the muscles of the face, shoulder blades, and upper arms.
FSHD may be inherited from either parent in an autosomal dominant pattern, meaning only one mutated gene is necessary to have the disorder; or occur without a prior family history.It is caused by the abnormal expression of a gene called DUX4, which produces a protein that is toxic to muscle cells.Normally, the DUX4 gene is silent in adult cells, but in FSHD a genetic mutation allows its expression, resulting in muscle degeneration and fat infiltration of skeletal muscle.Signs and symptoms of FSHD are often first noticeable in adolescence or early adulthood; and are usually asymmetrical, affecting only one side of the body.One of the earliest signs is facial muscle weakness, which can result in difficulty whistling or using a straw, inflating balloons, closing the eyes fully during sleep, or even smiling.Another typical sign is weakness in the muscles that hold the scapula, or shoulder blade, in place.
This results in scapular winging and difficulty raising the arms above shoulder height.Other areas, such as the abdomen, hip girdle, and legs may also be affected.
Abdominal weakness can result in a protuberant abdomen and an exaggerated lordosis, which is the inward curvature of the spine at the lumbar region.
The lower abdominal muscles tend to be weaker than those in the upper abdomen, which results in the movement of the navel towards the head when flexing the neck.This is known as the Beevor sign.As the disorder progresses weakness in the leg muscles can result in difficulty holding the foot up while walking, which can lead to instability and increased risk of falls.
There may also be difficulty climbing stairs or raising up from a chair.Some individuals may also experience general symptoms, like chronic fatigue and muscle aches, which can sometimes be debilitating.Additionally, some individuals have associated non-muscular manifestations, such as hearing loss, breathing problems, anomalies in the blood vessels of the retina, and cardiac arrhythmias.Diagnosis of FSHD is primarily based on an individual’s history and physical examination.
Diagnostic tests, such as blood tests, imaging studies, or a muscle biopsy may be done to rule out other causes of muscle weakness.
The diagnosis can be confirmed if genetic testing identifies a mutation in one of the genes that regulate DUX4 expression.Treatment of FSHD is generally supportive, as there is still no effective treatment to cure the disorder.
Physical and occupational therapy, gentle stretching, and light exercise can be helpful to preserve flexibility and muscle strength.
For some individuals, using assistive devices, such as walking sticks, wheelchairs, or orthopedic aids, can help prevent falls and improve mobility and independence.In cases where there’s restricted mobility due to scapular winging, scapular fixation surgery can be done to improve shoulder function and range of motion.
Finally, genetic counseling is recommended for affected individuals and their families to help them understand the genetics of the disease, and to provide psychosocial support.Alright, as a quick recap, facioscapulohumeral muscular dystrophy is a genetic neuromuscular disorder that causes weakness in the muscles of the face and upper body, resulting in decreased facial mobility, scapular winging, and abdominal weakness, among other symptoms.
Diagnosis can be confirmed through genetic testing and treatment focuses on physical and occupational therapy to preserve muscle function and
Facioscapulohumeral muscular dystrophy: Video | Osmosis