Brachydactyly (symbrachydactyly)

TOPIC: Brachydactyly (symbrachydactyly)

Essential Information:
Brachydactyly (short digits): a term that refers to short fingers (and toes) relative to hand size.  Clinical features are abnormally shaped, hypoplastic and/or missing metacarpals and phalanges.
  • Etiology
    • unknown
    • manifests at gestational week 6-8
  • Genetics
    • depends on the specific type of brachydactyly
      • Defects in: Bone Morphogenic Protein (BMP), Indian Hedgehog (IHH), and HOX have been identified
  • Incidence
    • in general it is rare
    • however in types A3 (small finger middle phalanx) and D (thumb distal phalanx) may affect as much as 2% of population
  • Risk Factors
    • may be seen with other bone/joint deformity syndromes
 
Clinical Evaluation:
  • History / Exam Findings
    • ususally isolated, no family history of similar condition
    • single or multiple short digits isolated to one hand (unless part of syndrome)
  • Imaging / Lab Studies
    • plain radiographs to delineate bone morphology
      • common finding: abnormal physes (delta phalanx)
    • +/- genetic testing
  • Classification Schemes
    • Temtamy & McKusick (1978), five major types:
      • A:  usually middle phalanx involved (5 subtypes)
      • B: absence or hypoplasia of ends of the index to little fingers (+/- nail involvement)
      • C: brachydactyly with multiple phalanges and long ring finger
      • D: short distal phalanx thumb
      • E: short metacarpals (usually ring), normal phalanges 
Treatment:
  • Conservative
    • Occupational Therapy
      • for adaptive needs, but often not necessary
  • Surgical
    • cosmetic
      • ‘nubbin’ removal
    • bone lengthening for improved pinch
      • formation of satisfactory radial and ulnar ‘posts’
    • web-space deepening
Outcomes:
  • Prognosis
    • usually patient adapts well
    • functions as ‘assist hand’ depending on number and function of digits
  • Potential Complications
    • only potential ones related to specific surgical procedures
 
Recommended Readings:
  • Seitz WH Jr, Froimson AI. Digital lengthening using the callotasis technique. Orthopedics 1995;18:129 –138
  • Temtamy SA, McKusick VA. The Genetics of Hand Malformations. New York: Alan R Liss, INC; 1978.
  • Temtamy SA, Aglan MS.  Brachydactyly.  Orphanet J Rare Dis. 2008; 3: 15 (published online)
 
 
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