Twins share DNA and are often studied because of their peculiarity. In Italy, the National Register of Twins is active, on the initiative of the Istituto Superiore di Sanità, with the aim of helping to clarify which environmental, genetic and lifestyle factors influence the physical and mental health of the population. The participation of twins in studies and research is of great help in understanding the mechanisms of diseases and attempts to prevent them where possible.

One of the research projects is in Humanitas, which started a year and a half ago is dedicated to psoriasis, as explained by Professor Antonio Costanzo, Head of Dermatology, and Professor Carlo Selmi, Head of Rheumatology and Clinical Immunology, in a service for TGR Leonardo.


The study

“Psoriasis is a very frequent disease in the general population, affecting about 3% of the population and more or less a quarter of these people will also develop a form of arthritis, or an inflammation in the joints and other parts of their skeleton,” explained Professor Selmi.

To better understand psoriasis, 60 pairs of twins were examined: “We now have a list of 52 genes, which we are studying in greater detail and which in our opinion can contribute to causing psoriasis or psoriatic arthritis,” continued Professor Selmi.


The role of the environment

The environment affects epigenetics, that is, it is able to modify the ability of genes to be interpreted and so the disease can develop only in one of the twins. “We have been able to identify some genes that are methylated, that is modified, differently in the pair of twins. These are the target genes of the environment,” commented Professor Costanzo.

The next step is the confrontation with people with psoriasis who have, unlike twins, a different genetic heritage. “This will hopefully allow us to identify proteins and markers in the blood that can indicate if a person has a risk of psoriasis or psoriatic arthritis,” added Prof. Costanzo.

The study also aims to define the different forms of psoriasis and determine how important DNA and the environment is for each type.


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