Syndrome with characteristics of infancy onset hypotonia, feeding difficulties, breathing problems, dysphagia, severely delayed development of speech and motor skills, distinctive facial features, recurrent seizures and seizure-like episodes (muscle jerking, twitching, and stiffening). Brain abnormalities may also be present several of which are caused by reduced production of myelin or delayed maturation of myelin. Caused by a microdeletion occurring on the long (q) arm of chromosome 5 at a position designated q31.3. The deleted region typically contains at least three genes. The loss of one of these genes, PURA, is thought to lead to most of the characteristic features of the condition. The condition is not inherited.