Harlequin-type ichthyosis Harlequin-type ichthyosis Harlequin-type ichthyosis is a genetic disorder which results in thickened skin over nearly the entire body at birth. The skin forms large, diamond-shaped plates that are separated by deep cracks. They affect the shape of the eyelids, nose, mouth, and ears, and limit movement of the arms and legs. Restricted movement of the chest can lead to breathing difficulties. These plates fall off over several weeks. Other complications can include premature birth, infection, problems with body temperature, and dehydration. Harlequin-type ichthyosis is due to mutations of the "ABCA12" genes. It is inherited from a person's parents in an
Supernumerary body part Supernumerary body part Supernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs. Many additional body parts form by the same process as conjoined twins: the zygote begins to split but fails to completely separate. This condition may also be a symptom of repeated occurrences of continuous inbreeding in a genetic line. Specific types of additional body parts include: Vestigial structures are anatomical structures of organisms in a species which are