<prompt> Answer this question truthfullyCould you explain what Ellis-van Creveld syndrome is?  <response>: <reason> It involves numerous anomalies including post-axial polydactyly, congenital heart defects most commonly an atrial septal defect producing a common atrium, occurring in 60 of affected individuals, pre-natal tooth eruption, fingernail dysplasia, short-limbed dwarfism, short ribs, partial hare-lip, and malformation of the wrist bones fusion of the hamate and capitate bones. 