Brachydactyly
|
|
Brachydactyly is a medical term which literally means "shortness of the fingers and toes" (digits). The shortness is relative to the length of other long bones and other parts of the body. Brachydactyly is an inherited, usually dominant trait. It most often occurs as an isolated physical difference, but can also occur with other anomalies as part of many congenital syndromes.
Nomograms for normal values of finger length as a ratio to other body measurements have been published. In clinical genetics the most commonly used index of digit length is the ratio of the 3rd (middle) finger in cm to the hand length in cm. Both are measured in an open hand from the fingertip to the principal creases where the finger joins the palm and where the palm joins the wrist. A nomogram can be found in the Appendix of Jones, ed. Smith's Recognizable Patterns of Human Malformation, 5th edition, Philadelphia: Saunders (1997).
| Contents |
Brachydactyly Type A1
Brachydactyly type A1 is an autosomal dominant inherited disease. Features include: -
- Brachydactyly
- Short or absent phalanges
- Extra carpal bones
- Hypoplastic or absent ulna
- Short metacarpal bones
Brachydactyly Type A2
Type A2 is a very rare form of brachydactyly. The phalanges of the index fingers and second toes are shortened.
Other syndromes
In the above brachydactyly syndromes, short digits are the most prominent of the anomalies, but in many other syndromes (Down's syndrome, Rubinstein-Taybi syndrome, etc), brachydactyly is a minor feature compared to the other anomalies or problems comprising the syndrome.
External links
- [Brachydactylies (http://www.bdid.com/brachy.htm)]
- [Type A2 (http://www3.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=112600)]