5q31.3 Microdeletion Syndrome, also known as severe neonatal hypotonia-seizures-encephalopathy syndrome due to 5q31.3 microdeletion, is related to hypotonia and neurodevelopmental disorder with neonatal respiratory insufficiency, hypotonia, and feeding difficulties. An important gene associated with 5q31.3 Microdeletion Syndrome is PURA (Purine Rich Element Binding Protein A). Affiliated tissues include brain and heart, and related phenotypes are eeg abnormality and ptosis