Familial Congenital Absence of the Flexor Pollicis Longus

Congenital absence of the flexor pollicis longus (FPL) may occur with different degrees of hypoplasia and may be associated with other abnormalities such as craniofacial anomalies¹. As an isolated absence, it is a rare occurrence, so much so that it is considered the rarest congenital anomaly of the thumb². Exclusive FPL absence has been reported as occurring bilaterally in a few reports^{3, 4}. Treatment has been transfer of the flexor digitorum superficialis (FDS) of the ring finger. However, due to the paucity of literature it is not clear whether to treat at all and there are no reports of long-term results. We report a case of familial isolated congenital absence of the FPL. In two out of the 4 cases, the anomaly was bilateral. Genetic analysis was performed.