2.9. Rare diseases

Rare diseases include a great many (~6,000-8,000) conditions with significant differences in their aetiology, pathogenic mechanisms and clinical symptoms, that share the fact that they have a low prevalence in the general population (affecting 5 in every 10,000 subjects, according to the European Union’s definition).

They are frequently associated with early mortality (in approximately 30% of cases, life expectancy does not exceed 5 years), however they may have a chronic course with severe outcomes in terms of disability and quality of life.

At 31 March 2010, 94,185 cases and 485 rare conditions were recorded in the National Rare Diseases Register. The class of diseases most frequently reported nationwide is that of diseases involving the nervous system and sense organs, with a percentage of 21.05%. These are followed by blood disorders and those of the haematopoietic organs (20.6%), endocrine gland, eating, metabolism and immune system disorders (18.95%) and congenital malformations (15.04%) and subsequently, with very low percentage levels, conditions affecting the reproductive and urinary systems and infectious and parasitic diseases (0.6%), premorbid conditions of pre-natal origin (0.24%) and the category of conditions with poorly-defined symptoms, signs and clinical status (0.01%, i.e. just 9 cases).

Considering that the rare conditions currently monitored include both groups and individual illnesses, an analysis of the data shows that the groups of conditions most frequently reported are hereditary clotting defects (7,799 cases), undifferentiated connective tissue disorders (5,631 cases), and hereditary anaemia (5,128 cases). As far as the individual pathologies are concerned, the most frequently reported are keratoconus (3,837 cases) and amyotrophic lateral sclerosis (3,292 cases). However, it is important to stress that the data contained in the Register is still partial. Indeed, registers are not kept in all regions of Italy. Another factor that contributes to the underestimation of cases registered is the delay in diagnosis, implying late reporting of the case that consequently influences the estimation of its incidence and/or prevalence. The National Rare Diseases Register uses the same nomenclature and classification system adopted for the list of rare diseases appended to Ministerial Decree 279/2001 for administrative purposes: this makes it difficult to identify the diseases within the groups or when synonyms are used. To overcome these difficulties, it is therefore essential that the Register reaches a consensus in the classification system to be used for synonyms or the individual diseases inside the groups. The European Committee of Rare Disease Experts, of which Italy is a member, is currently devising an international classification of rare diseases, which may contribute to the review of the classification systems performed by the WHO.

In Italy, in 2010, the Orphanet database indicated that there were 1,715 professionals specialised in rare diseases, 649 diagnostic laboratories conducting a total of 3,400 types of test, 76 patient registers and 44 rare diseases networks. Research in the field is active, with over 750 dedicated projects, more than half of which involve basic genetic research, 20% are clinical studies, 9% preclinical studies on gene or cell therapy, 6% are studies dedicated to the development of diagnostic protocols and, to a lesser extent, studies aimed at the development of medicinal products, identification of biomarkers and epidemiological studies. Thirty Italian companies are currently conducting trials on 64 molecules of potential interest for rare diseases.