Anomalies of skin, hair and nails.
The skin is composed of two distinct parts, the dermis and the epidermis, the dermis being derived from mesenchyme and the epidermis from ectoderm. The amount and color of the melanin present in the epidermis are responsible for the differences in skin color of different races. The dermis is formed from a condensation of the underlying mesenchyme.
During the third month of the pregnancy the hairs begin to develop as cylindrical down-growths of epidermis into the underlying mesenchyme. The nails commence as thickened fields of ectoderm at the tip of each digit. Later they migrate onto the dorsal aspect of each digit but retain their innervation from the ventral surface. Eight congenital anomalies of skin, hair and nails are, ichthyosis, sequestration dermoid, hemangiomas, gray hair, pili torti, hypertrichosis, alopecia, and anonychia.
Skin layers via Wikipedia
Ichthyosis. This disease is often familial and has a genetic background. This disease is a congenital abnormality of cornification, associated with scaliness and dryness. The increased thickness of the epidermis is caused by retardation of the process of exfoliation of the cells of the stratum corneum, so that the cells are retained for a longer period than normal. Sequestration dermoid. This is a congenital cyst caused by the burying by skin fusion of ectodermal cells along the lines of closure of embryonic clefts and sinuses.
Hemangiomas. The capillary hemangioma is a sharply demarcated erythematous swelling which is present at birth or appears shortly afterward. These tumors usually regress and require no treatment. The cavernous hemangioma, is a reddish-blue spongy swelling composed of vascular channels, considerably larger than capillaries, which are filled with blood. These tumors usually require surgical removal.
Human hair via Wikipedia
Gray hair. occurs in albinism and is associated with lack of pigmentation in the skin and irides. Pili torti. The hairs are twisted and bent. This is a congenital familial disorder of hair growth. Hypertrichosis. The presence of excessive hair production may be localized or diffuse. The diffuse form may involve large areas of the body, even the face. The localized form may occur in the lumbar or sacral area.
Fingernail via Wikipedia
Alopecia. Loss of hair, total and localized forms of this condition occur. It is a result of congenital absence or lack of development of the hair follicles. In conclusion of these eight congenital anomalies is Anonychia. Absence of nails, is a rare anomaly. This may be restricted to one or more nails of the fingers and toes, and their development may never take place. Deformed nails may occasionally occur.