[Mirror hand deformity: a new phenotype with literature review].

We report the case of a child who presented polydactyly with eight triphalangeal fingers, no thumb or radius and ulnar dimelia. Hand, wrist, forearm and elbow function was compromised, particularly due to wrist stiffness in flexion, the absence of forearm pronation supination and severe limitation of elbow motion. In addition, the child underwent surgery for pyloric hypertrophy and also presented a multicystic kidney. We present the clinical, anatomic, electromyographic, genetic and therapeutic aspects of this rare deformity and discuss data presented in the literature.