Darier disease is a rare genetic disorder characterized by the wart-like blemishes of the skin. This condition may begin in adolescence, can be chronic, is not contagious and the severity varies among the affected individuals. People with this condition may improve at times but the lesions mostly recur. The prevalence of darier disease is estimated to affect 1 in 300,000 individuals in Scotland and 1 in 100,000 individuals in Denmark, although the exact global frequency is not known.
Causes
Darier disease is inherited in an autosomal dominant pattern meaning that a single defective gene from one of the parent can cause this disease. In some cases, this disease can develop as the result of a new genetic mutation with no history of its prevalence in the family.
The genetic mutation that causes this disease is identified as ATP2A2 which produces an enzyme known as SERCA2 (sarcoendoplasmic reticulum calcium ATPase) that acts as a pump to maintain the level of positively charged calcium atom (calcium ions) within the cells. The function of calcium ions is to act as signals that are essential for the healthy development and the function of the cells. A genetic mutation in the ATP2A2 results in the insufficient amount of functional SERCA2. Although this enzyme is expressed throughout the body, why it particularly affects the skin is not clear. However, with the insufficient calcium, it appears that desmosomes (necessary for the skin cells to stick together) do not assemble properly.
Symptoms
It can develop anywhere between the age of 6 and 20. It mostly occurs in areas of the scalp, upper arms, chest, knees, back, forehead and elbows. The common symptom is the itchiness. The affected part of the skin may be yellowish in colour, crusty and greasy. It can emit strong odour particularly in moist areas that may be the result of bacterial growth. It can also affect the mucous membranes and develop in the tongue, palate, cheek, gums and throat. The fingernails can also become affected that may split easily with streaks that have irregular texture. Pits or areas of hard skin can develop in the sole of the feet and the palms of the hands. Some individuals may experience flare-ups with exposure to the sun or with women during their menstruation. Additional features can include neurological disorders consisting of epilepsy, depression and intellectual disability.
Diagnosis
This condition is usually diagnosed by the physical skin appearance of the rashes and the family history. A small section of the skin is removed for a biopsy that is usually studied under the microscope which reveals abnormalities of the keratin tissue and the problem with the cell-to-cell adhesion.
Treatment
There is no cure or darier’s disease but treatment can help in the management of the symptoms. The mild cases can be managed with moisturizers, sun protection and avoiding sweating by wearing selective clothing. The topical corticosteroids and substances can soften the skin and reduce the inflammation. Antibiotics may be necessary to treat the secondary bacterial infection that can develop.
References
http://www.dermnetnz.org/topics/darier-disease/
https://ghr.nlm.nih.gov/condition/darier-disease#inheritance
http://www.britishskinfoundation.org.uk/SkinInformation/AtoZofSkindisease/DariersDisease.aspx
https://rarediseases.org/rare-diseases/keratosis-follicularis/
