Coming up:

 AGSD-UK Annual Conference,
Nottingham,
28-29 October 2017.

 

More about Type III

First reports of heart problems (cardiomopathy)
Although the first GSD III patients were recognized in the 1950's, it was not until 1972 that cardiac features of the disease were described. Miller and colleagues reported an infant who suffered from severe biventricular muscle enlargment, a process that is called hypertrophy. The infant died at 15 weeks of age due to heart failure. Two years later, two out of five patients with adult-onset myopathy were found to have heart failure. In 1979 the autopsy findings in a 4 year old child were described. The heart was enlarged with increased glycogen content. No activity of the debrancher enzyme could be detected in the cardiac muscle.

Soroka Medical Centre, Israel
The metabolic clinic at Soroka medical center in Isreal was established in 1966 by Prof. Moses who is still active and working with GSD patients. Prof. Moses was the first to systematically investigate the cardiac status in 20 GSD III patients aged 3 to 30 years. 35 patients having GSD III have been followed in the clinic during the last 30 years. We provide enzymatic as well molecular genetic diagnosis. 25 of the patients are of north-african Jewish origin. All these patients carry the same genetic mutation. Most of the patients enjoy good health and run normal and productive lives. Several complications however, were observed, including

  • Fatal cardiomyopathy (1 patient)
  • Severe liver disease (4 patients)
  • Incapacitating muscle weakness (1 patient)
  • Severe brain damage after hypoglycemic episode (1 patient)

 

Only one patient had symptoms of a heart problem, but her condition continued to deteriorate and she died at 30 years of age while she was waiting for heart transplantation. 19 out of the 20 investigated had ECG abnormalities suggesting thickening of the heart's muscle. Echcoardiography, which is an ultrasonic examination of the heart, could detect wall thickening in 13 out of 16 patients. These few patients were not enough to indicate the prevalence of heart problems among GSD III patients.

French study
Several years later, Cardiac examinations were performed on 18 French patients. Clinical examinations and chest X rays were always normal. ECG showed unspecific changes. Echocardiographic abnormalities were found in 5 of the 16 children studied. These findings remained stable during the follow up period, which was more than 3 years. No association was found between the presence of myopathy (skeletal muscle weakness) and cardiomyopathy.

American study
A similar study was done in in 3 north-American referral centers, where all patients with glycogen storage disease Type III were evaluated for cardiomyopathy and myopathy. All 10 North American patients with deficient debrancher enzyme in the liver and muscle had progressive myopathy, and 6 had progressive cardiomyopathy. Three patients with deficient debrancher enzyme activity in liver only had no clinical evidence of myopathy or cardiomyopathy. The authors concluded that clinical features of glycogen storage disease Type III correlate with the particular biochemical defect seen with the disorder.