Monarch Disease Ontology term MONDO_0008514 (syndactyly type 3) (SD3) is a rare congenital distal limb malformation characterized by complete and bilateral syndactyly between the 4th and 5th fingers. Also known as: GJA1 non-syndromic syndactyly, SD3, non-syndromic syndactyly caused by mutation in GJA1, syndactyly of fingers 4 and 5.