Hyperekplexia 1, also known as hkpx1, is related to molybdenum cofactor deficiency and hyperekplexia, and has symptoms including fever, muscle rigidity and opisthotonus. An important gene associated with Hyperekplexia 1 is GLRA1 (Glycine Receptor Alpha 1). The drugs Picropodophyllin and Cytarabine have been mentioned in the context of this disorder. Affiliated tissues include skeletal muscle and bone marrow, and related phenotypes are seizure and inguinal hernia