The discovery of this glycogenosis was due to the astute observation that a patient with myoglobinuria had predictably sky-high values of serum CK but extremely low values of LDH. LDH is a tetrameric enzyme composed of various proportions of a muscle-specific subunit (LDH-A) and a cardiac subunit (LDH-B). In addition to muscle symptoms, female patients may suffer from dystocia necessitating cesarian sections, and a few patients had dermatologic problems.