ABL1 is a causative gene for congenital heart defect and skeletal malformation syndrome (CHDSKM) and human ABL1 deficiency syndrome (HADS); CHDSKM is associated with gain-of-function while HADS is associated with 3′ truncating variants, likely escaping NMD. This evidence concerns the gene ABL1 and congenital heart defects and skeletal malformations syndrome.