There are genetic diseases whose transmission obeys the laws of Mendel: autosomal dominant (one parent is a carrier or suffering from the disease, the risk of transmitting the defective gene to offspring is one in two), autosomal recessive (both parents are carriers but they are not suffering from the disease. A quarter of children are suffering from the disease and a quarter of them will be healthy and does not transmit) or gender. They are genetic diseases called simple or single, which means that a single gene is responsible for the disease. When you are suffering from psoriasis, the probability of transmitting the disease to her children does not however Mendel's laws: it is much lower.