A large number of human gene defects can cause ectrodactyly. Ectrodactyly, especially can be caused by mutations in chromosome 7. The mutations in 7th chromosome can result in a contiguous gene syndrome such as growth impairment, manifestations, hernias, hearing loss, mental retardation, etc. This is why most cases of ectrodactyly are generally accompanied by another abnormality or linked to another syndrome. [8]
However, the syndrome is still a medical mystery, scientists still don't know exactly why, and they only know that the syndrome happen during pregnancy and involves in chromosome 7. [9]