Monday, June 23, 2014

Developing Diagnostic Tests for Common Diseases: Role of the Rare Diseases

In June, 2014, my book, entitled Rare Diseases and Orphan Drugs: Keys to Understanding and Treating the Common Diseases was published by Elsevier. The book builds the argument that our best chance of curing the common diseases will come from studying and curing the rare diseases.

Chapter 13 describes the diagnostic methods, for common diseases, that have come, and will continue to come, from research into the rare diseases.

In former times, the sole purpose of diagnostics was to apply a name of a disease to a clinical condition. If the name was known, a treatment could be applied. If no treatment was available, there was always prayer. Today, it is not sufficient to simply provide a name for a disease. Diagnosis today covers a wide range of activities, including:

-Risk prediction—Determining whether an individual is at increased risk of developing a disease at some unspecified future time.

-Screening—Determining whether an individual falls into a separable group of individuals who are likely to have the disease at the time of screening. After screening, further studies would be necessary to determine whether the individual actually has the disease.

-Early detection—Determining whether an individual has a disease at an early stage of development. Early detection is often confused with disease screening. Early detection determines whether an individual has the disease at an early, usually pre-clinical, stage. Screening (see above) determines whether an individual is likely to have the disease.

-Molecular diagnosis—Determining the presence of disease with a molecular technique performed on very small samples of tissues. Molecular diagnosis typically replaces, supplements, or confirms traditional diagnostic methods, such as surgical biopsy.

-Subtyping—Determining which biological subtype of disease applies to an individual.

-Response prediction—Determining whether an individual with a disease is likely to respond to a particular treatment.

-Staging—Determining the extent to which a disease has advanced within an individual.

-Surveillance for minimal residual disease and for recurrence. The objective of minimal residual disease surveillance is to determine whether there are any traces of disease, not observable by standard clinical examination, that persist following treatment. The objective of recurrence surveillance is to determine whether a disease has recurred after remission.

When we review these various new diagnostic activities, we see that they recapitulate the steps of disease pathogenesis: the conditions that place an individual at risk of developing disease, the earliest steps in pathogenesis, the development of precursor lesions, response pathways, and disease progression. New laboratory tests are designed to measure markers for the genes and pathways that account for the components of pathogenesis.

Chapter 13 explains that the genes and pathways that lead to rare diseases are the pathogenetic building blocks of common diseases. Hence, the diagnostic techniques applied to a common disease will likely draw on knowledge obtained from one or more rare diseases.

I urge you to read more about this book. There's a good preview of the book at the Google Books site. If you like the book, please request your librarian to purchase a copy of this book for your library or reading room.

- Jules J. Berman, Ph.D., M.D.

tags: complex diagnoses, clinical pathology, biomarkers, new biomarkers, molecular tests, rare diseases, orphan drugs, orphan diseases