As it happens, the rare diseases are much simpler, genetically, than the common diseases. The rare disease can be conceived as controlled experiments of nature, in which everything is identical in the diseased and the normal organisms, except for one single factor that is the root cause of the ensuing disease. By studying the rare diseases, we can begin to piece together the more complex parts of common diseases.
Four themes apply to rare diseases, as a group:
1. In the past two decades, there have been enormous advances in the diagnosis and treatment of the rare diseases. In the same period, progress in the common diseases has stagnated. Advances in the rare diseases have profoundly influenced the theory and the practice of modern medicine.
2. The molecular pathways that are operative in the rare diseases contribute to the pathogenesis of the common diseases. Hence, the rare diseases are not the exceptions to the general rules that apply to common diseases; the rare diseases are the exceptions upon which the general rules of common diseases are based.
3. Research into the genetics of common diseases indicates that these diseases are much more complex than we had anticipated. Many rare diseases have simple genetics, wherein a mutation in a single gene accounts for a clinical outcome. The same simple pathways found in the rare diseases serve as components of the common diseases. If the common diseases are the puzzles that modern medical researchers are mandated to solve, then the rare diseases are the pieces of the puzzles.
4. If we fail to study the rare diseases in a comprehensive way, we lose the opportunity to see the important biological relationships among diseases consigned to non-overlapping sub-disciplines of medicine.
Every scientific field must have a set of fundamental principles that describes, explains, or predicts its own operation. Rare diseases operate under a set of principles, and these principles can be inferred from well-documented pathologic, clinical, and epidemiologic observations. Today, there is no recognized field of medicine devoted to the study of rare diseases; but there should be.
Rare Disease Day is coming up February 29 (a rare day for rare diseases). In honor of the upcoming event, I'll be posting blogs all month, related to the rare diseases and to rare disease funding.
- Jules Berman (copyrighted material)
key words: rare disease, orphan drugs, orphan diseases, zebra diseases, rare disease day, disease complexity, common diseases jules j berman
