 Over the last ten years, Delta Theta Tau has contributed a great deal of time and money to the National Foundation for Ectodermal Dysplasias (NFED).The ectodermal dysplasia (ED) syndromes are a group of about 150 heritable disorders that affect the ectoderm, the outer layer of tissue in a developing baby.ED syndromes affect both males and females of all races and ethnic groups.