<prompt> McArdles disease causes muscle cramps and muscle fatigue with increased muscle glycogen. Which of the following enzymes is deficient?Hepatic hexokinaseMuscle glycogen synthetaseMuscle phosphorylaseMuscle hexokinase  <response>: Muscle Phosphorylase deficiency leads to a glycogen storage disease and , in young adults, an inability to do strenuous physical work because of muscular cramps resulting from ischemia. The compromised phosphorylation of muscle glycogen characteristic of McArdles disease compels the muscles to rely on auxiliary energy sources such as free fatty acid and ambient glucose. regarding glycogen storage disease GSD GSD type Disease name Enzyme defeciency GSD 1 Von gierkes Glucose 6 phosphatase GSD 2 Pompes Acid Maltase GSD 3 Coris Forbes Glycogen debrancher GSD 4 Andersons Glycogen branching enzyme GSD 5 Mc Ardle Muscle glycogen phosphorylase GSD 6 Hers Liver glycogen phosphorylase GSD 7 Tauris Muscle phosphofructokinase 