How do medications treat degenerative developmental disabilities?

Most forms of degenerative developmental disabilities cannot be treated by medications.  However, if the underlying cause of a degenerative developmental disability is a metabolic disorder, the progression of the disorder may be stopped or stabilized using medications and/or dietary treatments.  In other forms of degenerative developmental disabilities, medications are used to treat certain disease symptoms. For example, Rett syndrome can causes muscle problems and seizures, so medications may be used for these symptoms.