Brachydactyly

Brachydactyly
Different forms of brachydactyly
Classification and external resources
Specialty	medical genetics
ICD-10	Q68.1
ICD-9-CM	755.2-755.4
DiseasesDB	29782
MeSH	D059327

Brachydactyly (Greek βραχύς = "short" plus δάκτυλος = "finger"), 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 dysmelia, 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 dimensionless ratio of the length of the 3rd (middle) finger to the hand length. Both are expressed in the same units (centimeters, for example) and 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).

Types

There are several types of Brachydactyly:

Type	OMIM	Gene	Locus	Also known as/Description
Type A1, BDA1	112500	IHH BDA1B	5p13.3-p13.2, 2q33-q35	Brachydactyly type A1 or Farabee-type brachydactyly. BDA1 is an autosomal dominant inherited disease. Features include: Brachydactyly, Short or absent phalanges, Extra carpal bones, Hypoplastic or absent ulna and Short metacarpal bones.
Type A2, BDA2	112600	BMPR1B GDF5	20q11.2, 4q23-q24	Brachydactyly type A2, Brachymesophalangy II or Brachydactyly Mohr-Wriedt type. Type A2 is a very rare form of brachydactyly. The phalanges of the index fingers and second toes are shortened.
Type A3, BDA3	112700			Brachydactyly type A3, Brachymesophalangy V or Brachydactyly-Clinodactyly.
Type A4, BDA4	112800			Brachydactyly type A4, Brachymesophalangy II and V or Brachydactyly Temtamy type
Type A5, BDA5	112900			Brachydactyly type A5 nail dysplasia.
Type A6, BDA6	112910			Brachydactyly type A6 or Osebold-Remondini syndrome.
Type A7, BDA7				Brachydactyly type A7 or Brachydactyly Smorgasbord type.[1]
Type B, BDB (or BDB1)	113000	ROR2	9q22	Brachydactyly type B.
Type C, BDC	113100	GDF5	20q11.2	Brachydactyly type C or Brachydactyly Haws type.
Type D, BDD	113200	HOXD13	2q31-q32	Brachydactyly type D. Referred to inaccurately ("clubbing is a clinically descriptive term, referring to the bulbous uniform swelling of the soft tissue of the terminal phalanx of a digit")[2] as "clubbed thumbs".
Type E, BDE	113300	HOXD13	2q31-q32	Brachydactyly type E.
Type B and E	112440	ROR2 HOXD13	9q22, 2q31-q32	Brachydactyly types B and E combined, Ballard syndrome or Pitt-Williams brachydactyly.
Type A1B, BDA1B	607004		5p13.3-p13.2	Brachydactyly type A1, B.

Other syndromes

In the above brachydactyly syndromes, short digits are the most prominent of the anomalies, but in many other syndromes (Down syndrome, Rubinstein-Taybi syndrome, etc.), brachydactyly is a minor feature compared to the other anomalies or problems comprising the syndrome.

See also

• Clubbed thumb

References

1. Meiselman SA, Berkenstadt M, Ben-Ami T, Goodman RM (1989). "Brachydactyly type A-7 (Smorgasbord): a new entity". Clin. Genet. 35 (4): 261–7. doi:10.1111/j.1399-0004.1989.tb02940.x. PMID 2714013.
2. "Clubbing of the Nails: Background, Pathophysiology, Epidemiology".

External links

• Type A2 (broken link)
• Brachydactyly type A1 at NIH's Office of Rare Diseases
• Brachydactyly type A2 at NIH's Office of Rare Diseases
• Brachydactyly type A3 at NIH's Office of Rare Diseases
• Brachydactyly type A6 at NIH's Office of Rare Diseases
• Brachydactyly type A7 at NIH's Office of Rare Diseases
• Brachydactyly type B at NIH's Office of Rare Diseases
• Brachydactyly type C at NIH's Office of Rare Diseases
• Brachydactyly type E at NIH's Office of Rare Diseases
• Brachydactyly types B and E combined at NIH's Office of Rare Diseases