Erb-Roth dystrophy

Erb-Roth dystrophy is a primary degenerative neuromuscular disease of hereditary origin. Sometimes this pathology is called juvenile limb-girdle progressive muscular dystrophy.

Progressive Erb-Roth muscular dystrophy can begin in childhood or adolescence, but the age at which the disease begins varies widely, from 10 to 30 years. Both sexes are affected equally, although it was previously thought that adolescents and young men were much more likely to be diagnosed with the disease.

Neurologists note that Erb-Roth dystrophy that began in childhood progresses faster than in those who fell ill in adolescence or adulthood. In addition, in the latter case, the disease proceeds in a milder form.

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Causes of Erb-Roth dystrophy

According to the current version, the causes of Erb-Roth dystrophy are a genetic defect transmitted from one of the healthy parents - a healthy carrier of a mutated gene in paired non-sex chromosomes or in the X chromosome. These are genes such as 13q12, 17q12-q21.33, 4q12 and 5q33.

This type of inheritance is called autosomal recessive, and this is the way diseases associated with enzyme deficiencies and disorders of the structural transmembrane proteins α-, β-, γ- and δ-sarcoglycans are most often transmitted to offspring.

Progressive Erb-Roth muscular dystrophy occurs due to damage to muscle tissue and its atrophy. Among the assumptions regarding the mechanism of pathology development is the increased permeability of the membranes of striated muscle tissue cells (sarcolemma) due to insufficient synthesis of sarcoglycans - components of the dystrophin-glycoprotein complex proteins, which ensures the connection of the cellular skeleton of the contractile elements of muscle fibers of myofibrils with extracellular tissue structures. As a result of the deficiency of sarcoglycans, the amino acid-enzyme balance in muscle fibers is disrupted.

A certain role in the etiology of Erb-Roth muscular dystrophy can also be played by the protein isoenzyme creatine phosphokinase, or more precisely, its identified deficiency in muscle tissues and abnormally high levels in blood plasma. This enzyme catalyzes the reaction of oxidative phosphorylation of adenosine diphosphate (ADP) into adenosine triphosphate (ATP) in the mitochondria of muscle tissue cells, i.e. it maintains the muscle contraction cycle with energy.

Symptoms of Erb-Roth dystrophy

The main symptoms of Erb-Roth dystrophy, which begins to develop in children and adolescents:

• delay in the onset of independent walking;
• an awkward waddling gait (a "duck" type of gait due to symmetrical weakening of the muscles of the hip region);
• frequent loss of balance and instability (stumbling while walking and falling while running);
• difficulty getting out of bed, from a chair, bending over, going up and down stairs;
• protrusion of the shoulder blades (“winged” shoulder blades – a consequence of weakening of the anterior serratus muscles of the chest and the rhomboid muscles of the back);
• decrease in waist circumference (due to decreased tone of the transverse muscles of the chest, abdomen and iliopsoas muscles);
• pathological fatigue.

The disease progresses and there is constant general weakness and weakening of the muscular corset of the back and the muscles of the shoulder girdle, which leads to such defects of posture as hyperlordosis - deformation of the spine in the lumbar region with a convexity to the front. It is increasingly difficult for patients to hold any objects in their hands and raise their arms up. The facial muscles also lose mobility, which is accompanied by incomplete closure of the eyelids and protrusion of the lips (due to weakness of the orbicularis oris muscle).

Gradually, a decrease in muscle tone (hypotrophy) leads to thinning and flabbiness of muscle tissue with its replacement by fatty tissue and fibrous tissue, i.e. myodystrophy. And the characteristic symptoms of Erb-Roth dystrophy at later stages are: significant loss of muscle mass, stiffness of joint movement (flexion contracture), shortening of tendons (including the heel tendon) and almost complete loss of deep tendon reflexes of the lower extremities (knee and plantar). In approximately 20% of cases, patients with this disease develop cardiomyopathy.

Diagnosis of Erb-Roth dystrophy

Diagnosis of Erb-Roth dystrophy is based on physical examination of patients, study of family history and analysis of research data:

• genetic testing (used to determine the type of muscular dystrophy);
• electroneuromyography (ENMG);
• biopsy and biochemical examination of muscle tissue;
• general analysis of the steps;
• blood test for CPK (creatine phosphokinase);
• urine analysis.

Electromyography allows us to study not only the degree of neuromuscular transmission, but also to determine the level of direct muscle excitability, which is especially important for the differential diagnosis of Erb-Roth dystrophy with muscle pathologies of neurogenic origin.

Treatment of Erb-Roth dystrophy

It should be noted right away that, given the genetically determined nature of the pathology, treatment of Erb-Roth dystrophy is aimed at reducing the intensity of symptoms, alleviating the condition of patients and slowing the rate of progression of the disease.

Drug therapy for Erb-Roth muscular dystrophy includes drugs such as:

• vitamin complex (A, B group, C, D, E);
• ATP - to normalize cellular energy metabolism and activate membrane enzymes, as well as to increase antioxidant protection of the heart muscle (intramuscularly);
• Galantamine - used for progressive muscular dystrophy of cerebral palsy, myopathies. (tablets are taken orally at 4-12 mg per day - in 2-3 doses);
• Alpha-lipoic (thioctic) acid - normalizes metabolism: participates in the regulation of lipid and carbohydrate metabolism (Tiogama, Thiolipon, Espa-Lipon, Dialipon tablets are prescribed orally at 600 mg once a day);
• Riboxin is a precursor of ATP, stimulates metabolism, has anabolic, antiarrhythmic and antihypoxic effects (Riboxin tablets are taken orally at 1.2-2.4 g per day);
• Actovegin – is used to improve peripheral arterial or venous circulation, as well as for better healing of bedsores (prescribed 1-2 tablets three times a day).

Light massage, hydromassage, water procedures (swimming) and therapeutic exercise for all muscle groups are recommended. Exercises and physiotherapy help to maintain muscle strength and joint mobility as long as possible, which are inevitably reduced by Erb-Roth muscular dystrophy.

Prevention and prognosis of Erb-Roth dystrophy

Prevention of Erb-Roth dystrophy - like most other hereditary diseases - is impossible.

In clinical medicine, this pathology is not considered a fatal disease. However, the prognosis for Erb-Roth dystrophy is unfavorable. The disease progresses and 20-25 years after the onset of symptoms, as a rule, leads to loss of mobility and dependence on a wheelchair.

In addition, muscle atrophy affects the heart and respiratory system, causing secondary disorders - heart failure and lung infections, which lead to death. Mild forms of muscular dystrophy do not affect the life expectancy of patients.

In the summer of 2014, the Swiss pharmaceutical company Santhera Pharmaceuticals announced that clinical trials of the oral drug Omigapil, intended for the treatment of Erb-Roth congenital muscular dystrophy, would begin at the end of the year. The trials will be conducted at the National Institute of Neurological Disorders and Stroke (NINDS) of the National Institutes of Health in the United States (NIH USA) under the auspices of the Swiss Foundation for the Study of Muscle Diseases and the American organization of patients with muscular dystrophies Cure CMD.

And researchers in the US led by Professor Jerry Mendell have published the results of a trial of gene therapy based on the introduction of a modification of the adeno-associated virus AAV1 from the Parvoviridae family into an affected muscle cell (without integrating it into its genome). The virus causes a mild, clearly programmed immune response, which results in the restoration of alpha-sarcoglycan synthesis. So, perhaps, in the near future, a severe congenital disease - Erb-Roth dystrophy - can be cured.