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.