Facioscapulohumeral dystrophy (FSHD)

Synonyms

Facioscapulohumeral muscular dystrophy, FSHMD, Landouzy-Dejerine muscular dystrophy;

engl.: FSH Dystrophy, Facioscapularhumeral (Muscular) Dystrophy.

introduction

The Facioscapulohumeral muscular dystrophy, frequently FSHD abbreviated is the third most common form of hereditary muscle wasting. The name describes the muscle parts that are particularly severely affected at an early stage:

• face (lat. facies)
• Shoulder region (lat. scapula = Shoulder blade)
• upper arm (lat. humerus).

However, as the disease progresses, other muscle parts (leg, pelvic and trunk muscles) become increasingly weak. The first symptoms usually appear in adolescence and early adulthood, and the individual muscle groups in the two halves of the body are often affected to different degrees. The disease generally progresses relatively slowly, but the severity of the symptoms varies greatly between individuals. The genetic basis of the facioscapulohumeral Muscular dystrophy is known, but the exact mechanism of the disease has so far only been researched in stages. There is currently no causal therapy for the disease, but since the heart muscles are usually not affected, the patients usually have a normal life expectancy.

definition

The FSHD is a disease of the Muscular dystrophieswhich are characterized by the initially predominant infestation of facial, Shoulder girdle- and upper arm muscles. The disease only affects them Skeletal muscles, the heart muscles, however, are spared. In the meantime, different subtypes of FSHD can be differentiated, primarily through human genetic methods. This article refers to the most common type, the "classic“FSHD1A.

Epidemiology

The fazioskapulohumerale Muscular dystrophy occurs with a frequency of approx. 1:20000 equally common in both sexes, making it the third most common muscular dystrophy. The disease will autosomal dominant inherited, d. H. that children of those affected have a 50% risk of developing the disease themselves. Nevertheless, men are often more severely affected clinically than women and are diagnosed earlier, although the cause is unclear.

root cause

As the cause of the "classic“FSHD was based on the loss of a small fragment of genetic material Chromosome 4 detected. This presumably leads to a misdirected activity of neighboring gene regions. The exact mechanism of the disease FSHD is ultimately unclear, it is assumed that such a dysregulation of several genes that play a role in Muscle metabolism play, the regenerative capacity of the muscles is reduced, which ultimately leads to the loss of muscle tissue.

Differential diagnoses

Diseases of the muscles and muscles are primarily considered Nervous system: The (partial) failure of a nerve that supplies a certain muscle region, for example due to injury, or the failure of a brain region responsible for motor skills, e.g. B. as part of a Stroke are also expressed in the (partial) loss of function of this muscle area. The great difference in the course between individual patients makes different diseases come into question, which clinically represent a FSHD resemble. Differentiating it from other muscle diseases is not always easy, especially when the symptoms of those affected differ from the classic picture "Mimic-shoulder-arm weakness“Differs.

Symptoms

Most patients become clinically conspicuous in adolescence or early adulthood due to weakness in the muscles of the shoulders, upper arms and face that are particularly affected. These may include difficulties in lifting your arms above the horizontal, discomfort when performing overhead work (Wallpapering, Comb), drooping shoulders or similar bad postures. The differences in the degree of weakness between the two halves of the body are relatively characteristic. The weakness of the Facial muscles This can lead to the affected person appearing to have an “expressionless” or even “grumpy” facial expression, asymmetrical facial expressions, difficulties in closing the eyes completely or, due to the corners of the mouth hanging down, saliva running out of the mouth. If the trunk and hip muscles are affected in the further course, the patients have difficulty getting up from lying down and when climbing stairs, an attack on the lower leg muscles is often expressed in a weakness of the ankle muscles, which leads to frequent stumbling. Overall, the disease is slowly progressing, overall the course is one FSHD very different between individual patients: some patients experience hardly any restrictions into old age, on the other hand around 10-20% of those affected are dependent on a wheelchair in the later course of the disease. However, since the disease only affects the skeletal muscles, life expectancy is not restricted.In some cases, facioscapulohumeral muscular dystrophy can begin in childhood, where muscle wasting seems to take place more quickly, and the prognosis is less favorable overall.

There seems to be a connection FSHD with hearing impairments (high pitched hearing loss) and retinal changes, the clinical significance of which, however, is to be assessed as minor.

Diagnosis

As with all genetic diseases, it is very important to ascertain the family medical history; here there can be clear indications of a hereditary disease and its mode of inheritance. Only in the rarest of cases does FSHD develop spontaneously; there are usually other affected individuals in the patient's family.

The clinical examination can show a typical pattern of involvement of the muscles, this and the presence of other cases of illness in the family usually enable the clinical diagonism to be established. An EMG (electromyography) records the electrical activity within a muscle and helps to identify causative muscle (intrinsic) diseases from muscle changes due to e.g. B. to distinguish nerve damage. In terms of human genetics, the lack of the genetic sequence on chromosome 4 can be demonstrated by a blood test. Such an examination takes place in specialized human genetic centers of larger clinics and can e.g. B. also occur if there are no symptoms at all, but cases of illness are known in the family ("predictive diagnostics"). Such predictive diagnostics can be useful for the patient's career planning, but can also represent a psychological burden.

In a few cases, a typical change in the genetic sequence on chromosome 4 cannot be detected despite the corresponding clinical picture; these may be subtypes of FSHD ("atypical FSHD“).

therapy

There is currently no causal therapy for the facioscapulohumeral muscular dystrophy. Numerous attempts with the Asthma drug Albuterol, which also has an effect on muscle metabolism, was unsatisfactory, individual reports of therapeutic successes with the Antihypertensive drugs Diltiazem were initially refuted in a small clinical study. As with many hereditary diseases, the hope of researchers and those affected ultimately rests on future gene therapy.

Therefore, the conservative therapy a high priority: physiotherapy is used to preserve the affected person a maximum of mobility and to prevent bad posture.

Under certain circumstances, surgical measures can be used to correct incorrect posture, but they must be carefully considered.

The benefits of the physical training was not without controversy for a long time, as damage to the affected muscles from overuse is likely. In the meantime, however, those affected are advised to exercise lightly, especially because of its positive effects on Cardiovascular system and immune system.

Joining a self-help group can help patients deal with the disease, exchange experiences and get addresses from experienced therapists with muscle disorders.

forecast

Because the disease is exclusively the Skeletal muscles affected, the life expectancy of those affected is generally not restricted. Due to the relatively slow progression of the disease, the patient maintains a good quality of life for a long time. The course of the disease varies greatly between individual patients: while individual sufferers remain almost asymptomatic into old age, the majority of patients experience significant limitations in their ability to perform in everyday life and in their work as the disease progresses.