What is Type VII Glycogenosis (Tarui Disease, Myophosphofructokinase Deficiency)?
Type VII glycogenosis (Tarui disease, myophosphofructokinase deficiency) is a hereditary disease, which is caused by a lack of enzymes involved in the metabolism of glycogen; characterized by a violation of the structure of glycogen, insufficient or excessive accumulation of it in various organs and tissues.
Causes of Type VII Glycogenosis (Tarui Disease, Myophosphofructokinase Deficiency)
Type VII glycogenosis due to lack or complete absence of muscle phosphofructokinase. Inherited by an autosomal recessive type. The PFKM gene is located on the long arm of chromosome 1.
Symptoms of Type VII Glycogenosis (Tarui Disease, Myophosphofructokinase Deficiency)
Type VII glycogenosis characterized by muscle weakness, increased fatigue. These children walk on their fingers, which is associated with a shortening of the muscle fibers of the calf muscles. Hepatomegaly is characteristic.
Diagnosis of Type VII Glycogenosis (Tarui Disease, Myophosphofructokinase Deficiency)
To confirm the diagnosis of glycogenosis and establish its type in the hospital, a biopsy of the liver, muscles (sometimes skin) is performed, followed by histochemical examination; in this case, the glycogen content in the tissues and the activity of the enzymes involved in its metabolism are determined. With type II glycogenosis, the activity of acid α-1,4-glucosidase is also determined in the blood cells, as well as in the culture of fibroblast cells of the patient’s skin and muscles. Type II glycogenosis can be diagnosed prenatally by biochemical examination of cells of desquamating epithelium of the fetal skin located in the amniotic fluid obtained by amniocentesis.
Differential diagnosis in newborns is carried out with syphilis, toxoplasmosis, cytomegalovirus infection, liver diseases, at an older age – with Gaucher disease, Nimann-Peak disease, myatonia, xanthomatosis. Neuromuscular disorders can mimic progressive muscular dystrophy, amyotrophy – Sharko-Marie-Tooth neural amyotrophy and Verdnig-Hoffmann spinal amyotrophy (with a generalized form of type II glycogenosis); crucial in the diagnosis are relevant biochemical, electrophysiological and morphological studies of muscles.
Treatment of Type VII Glycogenosis (Tarui Disease, Myophosphofructokinase Deficiency)
The treatment is aimed at combating metabolic disorders, including with acidosis. In some cases, the use of glucagon, anabolic hormones and glucocorticoids is effective. Frequent meals high in easily digestible carbohydrates are essential for hypoglycemia. With muscle forms of glycogenosis, improvement is observed when dieting with a high protein content, the administration of fructose (inside 50-100 g per day), multivitamins, ATP. Attempts are being made to introduce missing enzymes to patients.
Patients with glycogenosis are subject to clinical observation by a doctor of the medical-genetic center and a pediatrician (therapist) of the clinic.
Prevention of Type VII Glycogenosis (Tarui Disease, Myophosphofructokinase Deficiency)
Prevention is not developed. To prevent the birth of a child with glycogenosis in families where there were similar patients, medical and genetic counseling is carried out.