Phenotypic Variability of Laurin–Sandrow Syndrome in Twin Siblings: Bilateral Mirror Hands with Tibial Involvement Treated by Staged Pollicisation

Laurin–Sandrow syndrome (LSS) is a rare congenital limb malformation defined by mirror-image polydactyly, often associated with tibial haemimelia and nasal anomalies. We report monozygotic twin siblings, evaluated at age 6 following international adoption, presenting with bilateral mirror hands and lower limb deformities without craniofacial involvement. Twin 1 presented with five-fingered mirror hands, complex syndactyly, a right transtibial amputation secondary to tibial haemimelia and contralateral equinovarus deformity. Twin 2 demonstrated bilateral polysyndactyly (six metacarpals with radial hypoplasia on one side; distal phalangeal duplication on the other), tibia vara and an accessory talus. Both underwent staged reconstruction, including syndactyly release and pollicisation of the preaxial-most digit. At 18-month follow-up, both achieved stable opposition and functional pinch (T-GAP scores 43–46). These cases highlight the significant intrafamilial phenotypic variability of LSS and demonstrate that favourable functional outcomes are achievable even with delayed surgical intervention.

Level of Evidence: Level V (Therapeutic)