 Marinus Pharmaceuticals, Inc. Nasdaq: MRNS, a pharmaceutical company dedicated to the development of innovative therapeutics to treat rare seizure disorders, announced today that the U.S. Food and Drug Administration FDA has granted Rare Pediatric Disease RPD Designation for the companys product candidate ganaxolone for the treatment of CDKL5 deficiency disorder CDD, a rare refractory form of pediatric epilepsy. 