What is Type II Glycogenosis (Pompe Disease)?
Pompe disease is type II glycogenosis, a rare genetic metabolic disorder, caused by the congenital absence of the enzyme lysosomal alpha-glucosidase, which is necessary to destroy glycogen, a substance that is an energy source for the body.
Causes of Type II Glycogenosis (Pompe Disease)
Pompe disease occurs as a result of a mutation in the lysosomal acid a-D-glucosidase gene, which ensures glycogen degradation in lysosomes. The type of disease inheritance is autosomal recessive. The gene is mapped on chromosome 17q23.
Pathogenesis during Type II Glycogenosis (Pompe Disease)
Enzyme deficiency leads to the deposition of non-hydrolyzed glycogen in the lysosomes of the muscles – cardiac and skeletal (“foamy” cells during morphological examination), which is accompanied by a picture of progressive muscular dystrophy. Clinical manifestations vary. There are early infantile, late infantile, juvenile and adult forms with a chronic course of the disease. The early infantile form occurs in the first months of life and is characterized by tearfulness, decreased motor activity, generalized progressive muscle weakness, including respiratory muscles. There is a delay in psychomotor development: the child does not hold his head, does not sit, palpation may reveal muscle hypertrophy. Difficulties of feeding due to dysphagia, malnutrition are revealed. The characteristic signs of the disease are macroglossia, severe cardiomegaly and hepatomegaly. Patients die before the age of 1 year from heart or cardiopulmonary failure,
Late infantile and juvenile forms begin in infancy, in early and older childhood, from 3 to 10 years. Clinical manifestations are characterized by progressive muscular dystrophy and visceromegaly (cardiomegaly, hepatomegaly, splenomegaly). Death occurs in the second decade of life from decompensated cardiopulmonary failure.
The adult form manifests itself in 2-3 decades of life and is manifested by symptoms of distal myopathy, thoracic scoliosis, lordosis, and slowly progressing heart failure. Patients live to old age.
Symptoms of Type II Glycogenosis (Pompe Disease)
The first symptoms appear in the first weeks of life up to six months after birth. An enzyme defect is found in the liver, kidneys, spleen, muscles, nervous tissue, and white blood cells. There is respiratory distress, anxiety, or adynamia. There is a lack of appetite, growth retardation, muscle hypotension. The sizes of the heart, liver, kidneys, and spleen increase. The heart acquires a spherical shape, in connection with myocardial hypertrophy, ECG changes appear. Often hypostatic pneumonia, bronchitis, pulmonary atelectasis occur, myodystrophy, hyporeflexia, spastic paralysis are observed. The muscle form of type II glycogenosis occurs only in muscles with a deficiency of acidic α-1,4-glucoisade. The disease manifests itself at a later date and in the clinical picture resembles myopathy.
Children’s form usually begins at the end of infancy or in early childhood. The degree of organ damage may vary among patients. The adult form of Pompe disease is also manifested by muscle weakness, as with other chronic muscle diseases. The onset of symptoms usually occurs in the second or fourth decade of life. With this type of disease, slow progression occurs and the heart is not affected.
Diagnosis of Type II Glycogenosis (Pompe Disease)
The diagnosis of Pompe disease is made taking into account the family history and biopsy data of skeletal muscles containing deposited glycogen in cells with no acid glucosidases.
An x-ray determines an increase in heart size due to all departments, congestion in the lungs.
A typical ECG, on which a shortening of the PQ interval is recorded, a very high and often wide QRS complex in the left precordial leads, an extension of the ventricular repolarization phase with T wave inversion and an arcuate ST interval.
On echocardiography revealed hypertrophy of the walls of all departments of the heart with a sharp decrease in their cavities during systole.
Treatment of Type II Glycogenosis (Pompe Disease)
There are no specific treatments for Pompe disease. The treatment is symptomatic, in the treatment of heart failure, the risk of using cardiac glycosides should be taken into account.
Forecast. Most children die before the end of the first year of life.