Hanhart syndrome (also known as Aglossia adactylia; Hypoglossia-hypodactylia syndrome; Peromelia with micrognathia) is a congenital disorder that causes an undeveloped tongue and malformed extremities and fingers. Hanhart syndrome (also known as Aglossia adactylia; Hypoglossia-hypodactylia syndrome; Peromelia with micrognathia) is a congenital disorder that causes an undeveloped tongue and malformed extremities and fingers.