A common first sign of FSHD, asymptomatic scapular fixator causing scapular winging and difficulty reaching above the shoulder level. Note asymmetry.

Facioscapulohumeral muscular dystrophy is a heritable muscle disease, often called FSH or FSHD. Progressive weakening and loss of skeletal muscle are its major effects. It has significant medical and health impacts on individuals, families, and society. (It is also known as Landouzy-Dejerine disease, after the two French neurologists who first documented it in the late 19th century.)

FSHD is among the most common forms of muscular dystrophy, affecting children and adults of both sexes. The cardinal feature of FSHD is the progressive loss of muscle strength. The disease’s name comes from the typical pattern of weakness at onset: the face (facio), shoulder girdle (scapulo), and upper arms (humeral). However, the disease can differ in the typical initial pattern of weakness: not every patient experiences facial muscle loss, and many develop muscle weakness in the legs and torso.

The symptoms can develop at any age, from infancy through advanced age. Many patients recall being unable to whistle, smile, or close the eyelids as a child. The majority of males are diagnosed by age 20, and females by age 30. About 4 percent of cases are diagnosed in children under the age of 5. These early-onset or infantile-onset (iFSHD) patients are at greater risk of having more severe symptoms and added health complications.

Although the progression of FSHD is variable, it is usually relatively slow. Asymmetry is a hallmark of FSHD. Most patients will observe that one arm (or shoulder blade, or lower leg) is weakened, while the other remains stronger. The reason for this asymmetry is unknown.

Early weaknesses of the muscles of the eye (difficulty closing the eye) and mouth (difficulty smiling, puckering the lips, or whistling) are distinctive for FSHD. Facial weakness in combination with weaknesses in the muscles that stabilize the shoulder blades, which result in “winging” of the scapula, is often the basis of the physician’s initial diagnosis of FSHD.

As the disease progresses, the lower and upper leg muscles are often affected. About 20 percent of FSHD patients overall will become dependent on a wheelchair or scooter.

Weakness in the abdominal muscles can cause a protuberant abdomen and lumbar lordosis (“sway back”). The lower abdominal muscles are usually weaker than the upper abdominal muscles. This results in a movement of the navel toward the head upon flexing the neck. Doctors call this a positive Beevor’s sign; it is not seen in many other diseases and is a physical characteristic very specific to FSHD.

FSHD can also have the following non-muscular manifestations: high-frequency sensorineural hearing loss in both ears, respiratory insufficiency, abnormalities of blood vessels in the back of the eye, and non-symptomatic cardiac arrhythmias.

In more than half of people with FSHD, high-frequency sensorineural hearing loss occurs in both ears; this should be checked in children and adults experiencing hearing difficulties.

Approximately half of FSHD cases also involve abnormalities of blood vessels in the back of the eye, but these lead to visual problems in less than 1 percent of cases. Since these abnormalities are not exclusive to FSHD, one must bear in mind that their presence alone in someone at risk for having FSHD is not sufficient for a diagnosis of FSHD.

Respiratory insufficiency is a more common problem, especially among patients who have become scooter or wheelchair dependent. These patients should have an annual consultation with a pulmonologist to monitor respiratory function and blood carbon dioxide.

Symptoms or signs can (but don’t always) include:

  • inability to whistle;
  • inability to sip through a straw;
  • eyes that don’t close fully during sleep;
  • difficulty with sit-ups and pull-ups;
  • shoulder blades that “wing” out;
  • difficulty raising arm above shoulder height;
  • foot drop (foot dorsiflexion weakness);
  • difficulty walking, climbing stairs, or rising from a seat;
  • falling;
  • weak lower abdominal muscles, protuberant abdomen, “Beevor’s sign”;
  • curved spine (lordosis).

Individuals with FSHD, particularly with more advanced or severe cases, can also experience:

  • episodes of “malaise” or “burning pain” in muscles;
  • severe pain from changes in posture and strain on remaining muscles;
  • chronic fatigue;
  • respiratory insufficiency (potentially life threatening);
  • symptomatic hearing loss;
  • Coats’ disease (symptomatic retinal vascular disease), though this is rare.

Additional information:

Clinical descriptions of symptoms

 “Generally, FSHD displays a characteristic gradual spread of muscle involvement, starting in the face and slowly progressing to the shoulder and upper-arm musculature and to the abdominal and foot-extensor muscles” (1). “Foot dorsiflexion weakness leading to footdrop is an early manifestation of FSHD and one amenable to the use of molded ankle-foot orthoses (AFO)” (2). “The most common initial symptom is difficulty reaching above shoulder level. Less common presentations include foot drop (such patients, however, almost invariably have compensated), asymptomatic scapular fixator, and facial weakness on examination. Truncal weakness is an early and frequent manifestation that is easily overlooked during examination of these patients. Weak abdominal muscles result in a protuberant abdomen and contribute to the lumbar lordosis. Lower abdominal muscles are weaker than the upper abdominal muscles, causing a strikingly positive Beevor’s sign, a physical finding fairly specific for FSHD” (2). “Associated non-skeletal muscle manifestations include high-frequency hearing loss as well as retinal telangiectasias, both of which are rarely symptomatic” (2). “Approximately half of the patients present with subclinical high-tone hearing loss and retinovasculopathy” (1). Respiratory involvement in FSHD is not typical but can be seen, especially in patients with severe FSHD. Symptoms and signs of respiratory insufficiency should be sought during routine clinic visits in patients with severe FSHD, and regular monitoring of respiratory function instituted. “Symptomatic respiratory insufficiency can be initially managed with nighttime noninvasive pressure support (BiPAP) but may in severe cases require the use of a ventilator” (2). 1. van der Maarel SM, Frants RR. The D4Z4 repeat-mediated pathogenesis of facioscapulohumeral muscular dystrophy. Am J Hum Genet. 2005 Mar; 76(3):375-86. Review. Click to read Abstract 2. Tawil R, van der Maarel SM. “Facioscapulohumeral muscular dystrophy.” Muscle Nerve. 2006 Jul; 34(1):1-15. Review. Click to read Abstract

Other Medical Terms for FSHD

  • Landouzy-Dejerine Muscular Dystrophy—The older name for FSHD; named after Landouzy and Dejerine, who first described the disease in 1885.
  • Facioscapulohumeral Disease—The term used by Dr. George W.A.M. Padberg in 1980 to describe FSHD as a multi-system, whole body disease.
  • Facio-Scapulo-Humeral Muscular Dystrophy—A less common variation of the spelling of facioscapulohumeral muscular dystrophy.
  • Fascioscapuohumeral Muscular Dystrophy—A less common spelling alternative for FSHD.
  • Scapulohumeral Muscular Dystrophy—A facial-sparing form of dystrophy whose genetic locus may be the same as that for FSHD. There is no demonstrable facial weakness in affected individuals.
  • Coats’ Disease—Also called retinal telangiectasis, a disorder characterized by a defect of retinal vascular development that results in vessel leakage, subretinal exudation, and retinal detachment. The disorder was first reported by Coats in 1908. It is usually associated with infantile or early-onset FSHD.
  • Bilateral Sensorineural Hearing Loss—A high-frequency hearing loss caused by nerve damage in both ears. Usually associated with and clinically symptomatic in infantile or early-onset FSHD.
  • Hypercarbic Respiratory Insufficiency—Respiratory insufficiency caused by high levels of carbon dioxide (CO2) in the blood.