Academy of Medical Sciences of I.R. Iran Archives of Iranian Medicine 1029-2977 20 9 2017 09 01 De novo Mutation in CACNA1S Gene in a 20-Year-Old Man Diagnosed with Metabolic Myopathy EN Masoud Edizadeh Raheleh Vazehan Fatemeh Javadi Shima Dehdahsi Mahsa Fadaee Mehrshid Faraji Zonooz Elham Parsimehr Fatemeh Ahangari Ayda Abolhassani Zahra Kalhor Zohreh Fattahi Maryam Beheshtian Ariana Kariminejad Mohammad Reza Akbari Hossein Najmabadi Shahriar Nafissi Journal Article The calcium channel, voltage-dependent, L-type, alpha 1S subunit (CACNA1S) gene encodes a skeletal Ca2+ channel which is involved in calcium-dependent processes such as muscle contraction and neurotransmitter release. Mutations in this gene have been accompanied by hypo- and normokalemic periodic paralysis, thyrotoxic periodic paralysis, and susceptibility to malignant hyperthermia. We report the clinical and genetic findings in a patient diagnosed with metabolic myopathy who had episodic attacks of muscle pain and weakness but with no family background of the disease. Next-generation sequencing (NGS) using a panel targeting metabolic myopathy and myotonia genes identified a de novo heterozygous pathogenic variant c.3724A>G, p.Arg1242Gly, in exon 30 of CACNA1S. As the second report of this variant, this case may broaden the CACNA1S-related disease spectrum to include normokalemic periodic paralysis.