Phosphorylase kinase deficiency in I-strain mice is associated with a frameshift mutation in the alpha subunit muscle isoform.

Heritable phosphorylase kinase (Phk) deficiency underlies a group of glycogenoses in humans, mice and rats that differ in mode of inheritance and tissue-specificity. It is assumed that this heterogeneity is caused by mutations affecting different subunits and isoforms of Phk. As the first Phk deficiency mutation to be identified, we report a single-nucleotide insertion in the coding sequence of the Phk alpha subunit muscle isoform of the I-strain mouse. This mutation accounts for the virtually complete enzymatic deficiency, the tissue specificity and the X-linked mode of inheritance in this mutant.