16p13.3 microduplication syndrome is a rare chromosomal anomaly syndrome resulting from a partial duplication of the short arm of chromosome 16 and manifesting with a variable phenotype which is mostly characterized by: mild to moderate intellectual deficit and developmental delay (particularly speech), normal growth, short, proximally implanted thumbs and other hand and feet malformations (such as camptodactyly, syndactyly, club feet), mild arthrogryposis and characteristic facies (upslanting, narrow palpebral fissures, hypertelorism, mid face hypoplasia, bulbous nasal tip and low set ears). Other reported manifestations include cryptorchidism, inguinal hernia and behavioral problems.

A rare genetic congenital limb malformation with characteristics of brachydactyly of fingers with major proximal phalangeal shortening and immobile proximal interphalangeal joints, as well as dorsally and proximally placed, non-articulating great toes (with or without angulation). Radiographic findings of hands include bilateral double first metacarpals and biphalangeal fifth fingers.