epidemiology
Last reviewed 01/2018
Congenital syndactyly is the second most common limb anomaly after polydactyly but is the most common anomaly in the hand. It has an incidence of about 1 in 2000 to 1 in 2500 live births. It accounts for between 4% and 20% of all congenital hand anomalies depending on the population studied. It is twice as common in males and half of all cases are bilateral. 10-40% of cases are familial and these are more likely to be bilateral. Where there is a familial predisposition, inheritance is thought to be autosomal dominant with variable penetrance.
It is more common in Caucasians.
In the hand the most common web space to be affected is the third (80%) followed sequentially by the fourth, second and, rarely the first. In the foot, the second web space is most frequently affected.