Rare diseases

Undiagnosed diseases

For a number of persons with rare diseases (RDs) a definite diagnosis remains undiscovered with relevant physical, psychological and social consequences. These group pf pathologies are named undiagnosed rare diseases (URDs). 

URDs include pathological conditions without a name, diseases with a well characterized and described phenotype (clinical manifestations of the disease), diseases with an unknown molecular basis or due to non-genetic factors.

URDs require other than specialised clinical centres, outstanding molecular investigations, common protocols and dedicated actions at national and international levels; the unmet needs of undiagnosed patients remain a global issue.

Many “Undiagnosed RDs programs” have been gradually developed on the grounds of a well-structured multidisciplinary approach.

The Undiagnosed diseases network international (UDNI) was established in 2014, (UDNI,; it was founded by five participants countries including Italy. The National centre for rare diseases – Italian National Institute of Health (ISS) is the Italian representative in this network.