Glycogen Storage Disease Type Ia (Von Gierke Disease)
Summary
Glycogen storage disease type Ia (GSD Ia) is a metabolic condition where the liver cannot release stored glucose into the bloodstream. The G6PC enzyme catalyses the final step of both glycogen breakdown and gluconeogenesis — without it, glycogen accumulates in the liver and kidneys, and the body cannot maintain blood glucose during fasting.
Practical takeaway
This matters when planning children. If your partner is Ashkenazi Jewish, carrier testing is particularly relevant. A genetic counsellor can discuss the dietary management required and the improving long-term outlook. Realised does not calculate reproductive risk or advise on reproductive decisions.
Evidence detail
What Carrier Status Means For You
You are not affected. One working copy of G6PC produces sufficient enzyme for normal glucose homeostasis. Your carrier status becomes relevant if your partner also carries a G6PC variant. Standard 25/50/25 recessive inheritance applies.
Population Context
GSD Ia occurs across all ethnic groups. The R83C variant is enriched in the Ashkenazi Jewish population. Other variants are more common in Chinese, Japanese, Hispanic, and European populations. Overall incidence is approximately 1 in 100,000 births.
Limitations
23andMe tests 1 of over 100 known pathogenic G6PC variants. Coverage is limited to the most common Ashkenazi variant. Comprehensive carrier screening covers substantially more variants. A "not detected" result provides only modest reduction in carrier risk for non-Ashkenazi individuals.