These include patent ductus arteriosus, a form of congenital heart defect (TFAP2B), myotonic dystrophy type 1, which is the most prevalent adult onset muscular dystrophy (CELF1), Pitt-Hopkins syndrome, which is characterized by intellectual disability, distinctive facial features, poor muscular development and abnormal breathing (TCF4), mental retardation with language impairment and with or without autistic features (FOXP1) and hyaline fibromatosis syndrome, characterized by abnormal growth of hyalinized fibrous tissue (ANTXR2). Here, FOXP1 is linked to Pitt-Hopkins syndrome.