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Glycogen storage disease type II in Israel
N Bashan1, R Potashnik, V Barash
1Department of Pediatrics, Ben-Gurion University of the Negev, Beer Sheva, Israel.
Insights
Alpha-glucosidase deficiency, a rare genetic disorder, is prevalent in Israel
Area of Science:
- Medical Genetics
- Metabolic Disorders
- Rare Diseases
Background:
- Alpha-glucosidase deficiency, also known as Pompe disease, is a rare inherited metabolic disorder.
- It is characterized by the deficiency of the enzyme acid alpha-glucosidase, leading to glycogen accumulation in cells.
- This accumulation primarily affects muscle tissue, causing progressive muscle weakness and dysfunction.
Purpose of the Study:
- To report the diagnosis and characteristics of alpha-glucosidase deficiency in Israel over 15 years.
- To investigate the prevalence and clinical presentation of the disease in different ethnic groups.
- To evaluate diagnostic methods and discuss implications for genetic counseling and prenatal diagnosis.
Main Methods:
- Retrospective analysis of 18 diagnosed patients with alpha-glucosidase deficiency.
- Clinical assessment, including disease type (infantile vs. juvenile).
- Enzymatic assays of alpha-glucosidase activity in muscle and leukocytes, including pH profiles.
Main Results:
- Eighteen patients diagnosed, predominantly Palestinian Arabs, with two from a Jewish Iraqi family.
- Most patients presented with infantile Pompe disease; one had the juvenile type.
- Muscle alpha-glucosidase activity was severely deficient (zero in 10/17 patients, <18% in others); leukocyte activity was variable and unreliable for diagnosis.
- Significant heterogeneity in enzyme pH profiles observed.
- High prevalence noted in the Arab population, despite low prevalence of other autosomal recessive diseases.
Conclusions:
- Alpha-glucosidase deficiency shows a notable prevalence in the Arab population in Israel.
- Muscle biopsy is a more reliable diagnostic indicator than leukocyte enzyme activity.
- Prenatal diagnosis should be offered to families with a history of this severe genetic disorder.
Abstract:
Eighteen patients with alpha-glucosidase deficiency have been diagnosed in Israel during the last 15 years. All patients were Palestinian Arabs, with the exception of two siblings from a Jewish Iraqi family. Clinically all patients had the infantile type (Pompe's disease), except one who had the juvenile type. Muscle glycogen content varied from 4 to 17% wet weight. Muscle alpha-glucosidase activity was zero in 10 of 17 patients examined. Among the seven patients in whom residual activity was present, the highest value was 18% of normal. Leukocyte alpha-glucosidase activity was highly variable, making this tissue unfit for enzymatic diagnosis of the disease. A marked heterogeneity was found in pH profiles of muscle and leukocyte alpha-glucosidase activity. A high prevalence of the disease in the Arab population was noted. In spite of a high rate of consanguinity, only a small number of autosomal recessively inherited diseases have been shown to be unusually prevalent in the Arab population. In view of the serious prognosis of this disease, prenatal diagnosis should be offered to affected families.