Brachydactyly


Brachydactyly
Different forms of brachydactyly

Brachydactyly (Greek βραχύς = "short" plus δάκτυλος = "finger"), is a medical term which literally means "short finger". 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. Brachydactyly can also be a signal that one will be at risk for heart problems as they age.

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 third (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.

Types

There are several types of Brachydactyly:

X-ray Brachydactyly type C (see below)
TypeOMIMGene LocusAlso known as/Description
Type A1, BDA1 112500IHH BDA1B5p13.3-p13.2, 2q33-q35Brachydactyly 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 112600BMPR1B GDF520q11.2, 4q23-q24Brachydactyly 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 112700Brachydactyly type A3, Brachymesophalangy V or Brachydactyly-Clinodactyly.
Type A4, BDA4 112800Brachydactyly type A4, Brachymesophalangy II and V or Brachydactyly Temtamy type
Type A5, BDA5 112900Brachydactyly type A5 nail dysplasia.
Type A6, BDA6 112910Brachydactyly type A6 or Osebold-Remondini syndrome.
Type A7, BDA7Brachydactyly type A7 or Brachydactyly Smorgasbord type.[1]
Type B, BDB (or BDB1) 113000ROR29q22Brachydactyly type B.
Type C, BDC 113100GDF520q11.2Brachydactyly type C or Brachydactyly Haws type.
Type D, BDD 113200HOXD132q31-q32Brachydactyly 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 113300HOXD132q31-q32Brachydactyly type E.
Type B and E 112440ROR2 HOXD139q22, 2q31-q32Brachydactyly types B and E combined, Ballard syndrome or Pitt-Williams brachydactyly.
Type A1B, BDA1B 6070045p13.3-p13.2Brachydactyly 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

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. S2CID 30099363.
  2. ↑ "Clubbing of the Nails: Background, Pathophysiology, Epidemiology". 15 July 2021. Archived from the original on 20 November 2021. Retrieved 7 November 2021. {{cite journal}}: Cite journal requires |journal= (help)
Classification
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