A major disease-causing gene for HypoPP has been identified as CACNA1S , which encodes the skeletal muscle calcium channel alpha-subunit with four transmembrane domains ( I-IV ) , each with six transmembrane segments ( S1-S6 ) .
O O O O O B-DiseaseOrPhenotypicFeature O O O O B-GeneOrGeneProduct O O O O B-GeneOrGeneProduct I-GeneOrGeneProduct I-GeneOrGeneProduct I-GeneOrGeneProduct I-GeneOrGeneProduct O O O O O O O O O O O O O O O O O