Some of the dermal diseases related to the skin could be hereditary. However, heredity in most cases doesn’t directly lead to a skin disease as is the case with other hereditary diseases. In hereditary skin diseases, the mere qualities or DNA patterns are genetically passed on and needs an external stimulant to create the skin complication.
Most of the parameters related to skin including texture of the hair, color and pigmentation of the skin, even its thickness in some cases are qualities that are passed on genetically and hence can be assumed to be under genetic control.
The genetic constitution is hence responsible in some cases to cause skin diseases but the expression of the skin diseases finally is through the effect of an external factor or a hormonal change caused by an external factor. Psoriasis and atopic eczema are two hereditary diseases whose conditions are passed on genetically but they break out only when there is an external factor which could be sunlight or excess stress.
While the former is an external factor, the latter is more of a body’s internal factor. Thus although hereditary diseases are inherently passed through genetics, they will break out only after external or internal stimuli at some point of time.
Another genetic skin problem is excess pigmentation also known as mole or birthmark. This condition referred to as nevi, could be due to differences in the concentration of skin cells or the excess presence of melanocytes or increases concentration in some parts of the skin. Some known cases of nevi also include reduced blood flow to patches of skin without any apparent disorder, leading to pale patches on the skin.
Epidermolysis bullosa is another skin disease passed on through heredity and can be identifies at birth because of its excessive scarring and blistering. Xeroderma pigmentosum is another case where the sunlight induces damage onto the skin cells. This condition which is sometimes cancer is when the enzymes cannot cure the resultant damage. Albinism is another disease that can be hereditary too.
Another condition called vitiligo is characterized by white patches on the skin due to the destruction of melanocytes or skin coloring substances in the skin. The cause of this complication is fully not clear but there are chances of it being a genetic case. Blashko’s lines which are patterns or stripes formed on the skin could also be because of inherent DNA patterns.