GSD9 is now recognised as one of the more prevalent forms of GSD, accounting for 25% of all people affected by GSD.
There are four variants, sometimes known as a, b, c and d, but now going by the names of:
• PHKA2 (formerly a). This is carried on the X part of the gene and is normally seen in males, however some female carriers are affected. Some 75% of people with GSD9 have this liver variant.
• PHKB (formerly b). Only 20 people have been reported to have this type which affects the liver and muscles.
• PHKG2 (formerly c). This is a recessive form of GSD9 with liver and muscle symptoms.
• PHKG1 (formerly d and PHKA1). This primarily affects the muscles.
Main signs of most GSD9 sub-type
- An enlarged liver (hepatomegaly) due to increased glycogen storage
- Hypoglycaemia (problems with maintaining blood sugar).
Muscle problems are present in some variants. A major feature is the wide variety of symptoms from person to person.
The information for this webpage came from this article which can be accessed here. (The paper does not cover the PHKG1 / GSD9d muscle form.)
View the paper on GSD6 and GSD9.
Muscle type PHKG1 / GSD 9d
For this form, please see the panel in the diagnosis and follow up section.