Polydactyly is a condition that describes having more than the normal amount of fingers or toes. This is a congenital condition meaning people are born with this condition. Another abnormality of the fingers or toes is called syndactyly which is having one or more fingers or toes fused together or connected by webbing. What causes polydactyly?
During fetal development in the womb, the cells become specialized and form the parts of the body. In some cases, an error occurs and the cells cause deformities by not performing their normal function or following the normal patterns of development. Polydactyly can be an inherited condition, part of a developmental disorder, or one symptom of a genetic syndrome.
Genetic syndromes occur when the cells do not behave normally during fetal development. Genetic syndromes tend to cause several symptoms. Unlike heredity, genetic syndromes are a developmental accident rather than the normal acquisition and blend of genetic traits from the parents. In genetic syndromes that can cause polydactyly, the polydactyly is considered a minor symptoms since the other symptoms cause more impairment of functioning and health.
The genetic syndromes that can cause polydactyly are rare conditions. One example of a genetic syndrome that causes polydactyly is short rib-polydactyly syndrome. As the name implies, this condition causes short ribs and a narrow rib cage as well as polydactyly.
Carpenter syndrome is a genetic syndrome that causes polydactyly and syndactyly. This syndrome can also cause growth retardation, low IQ, facial deformities, low-set ears, eye problems, undescended testes, umbilical hernia, heart defects, and other finger and toe deformities.
One chromosomal abnormality that causes polydactyly is Chromosome 13 trisomy. Chromosomes are typically in pairs with one chromosome being inherited from the mother and one from the father. In chromosome trisomy disorders, there are three copies of a chromosome instead of two. With Chromosome 13 trisomy, there are three copies of chromosome 13.
In addition to polydactyly, this can cause cleft palate and eye defects. Most infants born with this disorder die within months. Very few people with Chromosome 13 trisomy live to be ten years old or older.
When a person has polydactyly, the person may not have a complete extra finger or toe. In some cases, only a top portion of a finger or toe is attached to an otherwise normal finger or toe. The extra finger or toe may be much smaller than the normal fingers and toes. Many times, polydactyly can be surgically corrected by removing the extra fingers, toes, or partial digits.