Icahn School of Medicine at Mount Sinai
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Genetic Testing Lab

Test Catalog Molecular Genetics Laboratory Glycogen Storage Disease Type Ia

Glycogen Storage Disease Type Ia

Test Description:
Glycogen Storage Disease Type Ia (GSD Ia) is an autosomal recessive metabolic disorder that is caused by deficiency of microsomal glucose-6 phosphatase (G6Pase) activity, which catalyzes the final step of glycolysis. This results in severe hypoglycemia, hepatomegaly, growth retardation and a bleeding diathesis. In addition, lactic acidemia, hyperlipidemia and hyperuricemia in patients lead to long-term complications that include hepatic adenomas, osteoporosis and progressive renal disease. The estimated worldwide frequency of GSD Ia is 1 in 100,000, but the carrier frequency in the Ashkenazi Jewish population is estimated to be 1 in 64. Based on the data reported from American Ashkenazi Jewish GSD Ia patients, screening for p.R83C and p.Q347* in the G6PC gene is expected to identify greater than 95% of carriers in this population. Carrier screening for GSDIa may be considered for individuals of Eastern European (Ashkenazi) Jewish ancestry before or during pregnancy.

Full gene sequencing is available for reproductive partners of known mutation carriers. Prenatal diagnosis is also available. Prior to ordering prenatal testing, please contact our laboratory t 212-241-7518 to discuss.

References:
1. Lei K. et al., (1993) Mutations in the glucose-6-phosphatase gene that cause glycogen storage disease 1a. Science 262:580-583.
2. Lei K. et al., (1995) Genetic basis of glycogen storage disease Ia: prevalent mutations at the glucose-6-phosphatase locus. Am J Hum Gen 57:766-771.
3. Ekstein J. et al., (2004) Mutation frequencies for glycogen storage disease Ia in the ashkenazi jewish population Am J Med Gen 129A:162-164.
4. Scott, S.A., Edelmann, L., Liu, L., Luo, M., Desnick, R.J. and Kornreich, R. Experience with carrier screening and prenatal diagnosis for sixteen Ashkenazi Jewish Genetic Diseases. Hum. Mutat. 31:1-11, 2010.

Specimen Requirements:
Post-natal: Two 5-10 mL tubes of anticoagulated blood in EDTA (lavender top) or two 5-10 mL tubes of anticoagulated blood in ACD (yellow top).

Prenatal: 

  • Chorionic Villi: 5-10 mg in conical tube with sterile saline OR transport media
  • Amniotic Fluid: 10 ml in conical tube
  • Cultured Cells: two confluent T-25 flasks

Additionally, please send:

  • 5-10 ml maternal blood in EDTA (lavender top) required to perform MCC studies on all prenatal samples and in case maternal confirmation studies are necessary
  • 5-10 ml paternal blood in EDTA (lavender top) in case paternal confirmation studies are necessary

Shipping: Send at room temperature.

Turnaround Time: 10-14 days

CPT Code: 81250

Consent and Requisition Forms: Carrier Screening Requisition and Consent [PDF]

Additional Information: Expanded Ashkenazi Jewish Carrier Screening Brochure [PDF]

Related Tests: Ashkenazi Jewish Carrier Test Panel

Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss.