Lamellar ichthyosis or congenital ichthyosiform erythrodema). In around 10% of cases the baby sheds this layer of skin and has normal skin for the rest of its life. This is known as "self-healing collodion baby". The remaining 15% of cases are caused by a variety of diseases involving keratinization disorders. Known causes of collodion baby include ichthyosis vulgaris and trichothiodystrophy. Less well documented causes include Sjögren-Larsson syndrome, Netherton syndrome, Gaucher disease type 2, congenital hypothyroidism, Conradi syndrome, Dorfman-Chanarin syndrome, ketoadipiaciduria, koraxitrachitic syndrome, ichthyosis variegata and palmoplantar keratoderma with anogenital leukokeratosis. Since many of these conditions have an autosomal recessive inheritance pattern, they
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