Polydactyly is a congenital anomaly that consists of the presence of more than five fingers on hands or feet. This condition does not have adverse effects for the life of those who suffer it. Some negative effects of this strange condition can be aesthetic, since normally it does not generate great physical inconveniences.
Polydactyly is a non-symptomatic anomaly. However, it can happen that it is present as a symptom of a syndrome or major disease, such as Bardet-Biedl syndrome, or Greig Cephalopolysyndactyly syndrome (do not try to read this man's name aloud).
The causes of this anomaly are not entirely clear. It is known that it is a genetic mutation, therefore it is suspected that there may be a hereditary factor. However, this has not been proven and several isolated cases of polydactyly have been reported.
Types of polydactyly
The criterion for classifying cases of polydactyly is the location of the remaining finger. According to the Seattle Children's Research Institute there are three types of polydactyly.
If the extra finger is before the thumb, it is called pre-axial polydactyly. If the extra finger is after the little finger, it is called post-axial polydactyly. And finally, if the extra finger is between any of the fingers or toes, it is called central polydactyly.
Pre-axial polydactyly is also known as radial polydactyly when the abnormality is in the hands, or tibial polydactyly when it is in the feet.
@cervantes