In central polydactyly there is the duplication of the second, third and fourth finger. For upper extremity, the terms such as radial, central and ulnar are used, while terms such as tibial, central, and fibular are proposed for polydactyly in the lower extremity.
Rare occurrence of polydactyly is called “crossed polydactyly”, which involves the preaxial involvement of one extremity is coupled with the postaxial of the opposite end of the body .
- Advanced Bone Age
Bone Age CANT1 105650RDiamond-Blackfan RPS19, RPL5, RPL11 223200UDisorganization, Mouse, Homolog of * UDonnai (1988) Meckel-like Syndrome220500RDOOR126500UDouble Nail For Fifth Toe607323DDuane-Radial Ray Syndrome SALL4 * UDuplication of Lower Limb-Plus129540UEctodermal [ncbi.nlm.nih.gov]
Since foot and hand polydactyly is associated with the congenital defects, genetic workup and medical examination are recommended. Polydactyly has also rarely been associated with congenital anomalies such as Down syndrome, Trisomy 13 and Meckel syndrome .
- Prenatal ultrasound: Transvaginal ultrasound at 9 weeks and 13 weeks is a reliable diagnostic tool as the fetal finger buds develop at this stage. If polydactyly is suspected, thorough ultrasound must be done to identify any associated syndrome, such as Trisomy 13 and Meckel Gruber syndrome.
- Radiographs: In order to know if the skeletal elements contain a rudimentary digit, radiographs can be done .
- Histologic finding: Hyperkeratosis and acanthosis in the dermis are seen in patients with rudimentary polydactyly.
Prognosis is excellent for children with polydactyly (isolated or syndactyly). The patient post surgery can use the fingers and the toes. In individuals or children with additional birth defects, the prognosis is poor .
Complications related to polydactyly is associated with the surgical intervention for managing polydactyly.
Polydactyly can occur either as an isolated trait or with other syndromes. A positive family history in almost 30% of cases has been observed .
Knowledge of the prevalence of polydactyly is limited. Genetic and ethnic factors can influence of the nature of polydactyly in the general population.
Preaxial polydactyly is common in Asian populations (South China, Hong Kong and Japan) with 90% of all the reported cases observed in this population. Autosomal-dominant transmission is suspected in children with African Black and African American. In blacks, the occurrence of postaxial polydactyly is almost more frequent than in whites  .
Some other factors that increase the chances of polydactyly in children are:
- Male gender
- Low maternal education
- Recurrence of first-degree relatives
Mutation of the specific gene location causing limb development is responsible for polydactyly. In mammals, there is a cluster of the genes identified as homeobox or hox genes which corresponds to the 5 domains across the limb bud. It is found that the mutation of the HOXD13 gene is often associated with synpolydactyly.
No known preventive measures for polydactyly and syndatyly is known .
One of the congenital digital anomalies of the hand and foot is polydactyly. Often it appears in association with other birth defects. Polydactyly can be due to autosomal-dominant or autosomal-recessive gene mutation .
Polydactyly is a common type of congenital digital anomaly which manifests as an extra digit in the foot or hand.
Polydactyly can occur with the other syndromes or as an isolated case. It can occur due to autosomal-dominant or autosomal-recessive mutation. Family history, African race and male gender contribute to polydactyly.
In polydactyly, there is an appearance of the extra digit in any limb.
Surgical removal of the extra digit is the recommended treating polydactyly.
- Hosalkar HS, Shah H, Gujar P, Kulkarni AD. Crossed polydactyly. J Postgrad Med. Jul-Sep 1999;45(3):90-2.
- Cohen MS. Thumb duplication. Hand Clin. Feb 1998;14(1):17-27.
- Hung L, Cheng JC, Bundoc R, Leung P. Thumb duplication at the metacarpophalangeal joint. Management and a new classification. Clin Orthop Relat Res. Feb 1996;31-41
- Klaassen Z, Shoja MM, Tubbs RS, Loukas M. Supernumerary and absent limbs and digits of the lower limb: A review of the literature. Clin Anat. Jan 3 2011.
- Friedman, William F., and John S. Child. "Congenital Heart Disease in the Adult." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw-Hill, 1997.
- Castilla EE, Lugarinho R, da Graça et al. Associated anomalies in individuals with polydactyly. Am J Med Genet. 1998 Dec 28;80(5):459-65.
- Malik S, Grzeschik KH. Synpolydactyly: clinical and molecular advances. Clin Genet. Feb 2008;73(2):113-20.
- Petry P, Polli JB, Mattos VF, Rosa RC, Zen PR, Graziadio C, et al. Clinical Features and Prognosis of a Sample of Patients With Trisomy 13 (Patau Syndrome) From Brazil. Am J Med Genet A. Apr 23 2013.
- Bromley B, Shipp TD, Benacerraf B. Isolated polydactyly: prenatal diagnosis and perinatal outcome. Prenat Diagn. Nov 2000;20(11):905-8.
- Morley SE, Smith PJ. Polydactyly of the feet in children: suggestions for surgical management. Br J Plast Surg. Jan 2001;54(1):34-8.
- Rudolph, Colin D., and Abraham M. Rudolph, editors. Rudolph's Pediatrics. 21st ed. New York: McGraw-Hill, 2003.