July 2017
7/31/2017 | BY Scott Riley, MD - Shriners Hospital for Children, Lexington, KY
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
- depends on the specific type of brachydactyly
- 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
- plain radiographs to delineate bone morphology
- 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
- Temtamy & McKusick (1978), five major types:
- Conservative
- Occupational Therapy
- for adaptive needs, but often not necessary
- Occupational Therapy
- Surgical
- cosmetic
- ‘nubbin’ removal
- bone lengthening for improved pinch
- formation of satisfactory radial and ulnar ‘posts’
- web-space deepening
- cosmetic
- 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)