Abstract
We report a rare limb defect named as fibular aplasia, tibial campomelia, and oligosyndactyly (FATCO) syndrome in a female monozygotic twin with a normal twin sister, presented with anterior tibia pseudarthrosis, oligosyndactyly, and pes equinovarus. Radiographic examination displayed the absence of left fibulae, anterolateral pseudarthrosis of left tibia, and the absence of some metatarsus and phalangeal bones. Our case report is the first to report that only one of the identical twins was affected by FATCO syndrome, which is a significant finding because the pathogenicity of FATCO syndrome is yet to be identified, and this clinical case may provide a new insight for discovering the etiology of FATCO syndrome.