This episode discusses two children - one of whom I saw as a floppy baby on the neonatal unit.  She turned out to have a condition known as Prader Willi syndrome and I discuss what this condition is.  I also describe a little boy who I met because of his difficult to treat epilepsy - he had a neurological disorder called Angelman syndrome.  These two conditions are both due to a loss of genetic material from one chromosome (chromosome 15) but these completely different conditions arise depending on whether the father's or the mother's DNA is missing. I also discuss a complication of the epilepsy which can occur in Angelman syndrome - a problem called non-convulsive status epileptics.