The NEJM has an interesting editorial on using whole individual genomes to assess for risk factors of disease.

The editorial concisely introduces the function of genomics and mutation analysis in medicine.  It also addresses the current limitations and the promising future of the technology in patient care.

If you are unfamiliar with the medical (and other scientific) literature, editorials such as this often accompany the presentation of original research.  In this case, the original study was this paper on Charcot-Marie-Tooth disease.

As it was the inspiration for the editorial, the original paper shows how sequencing the genomes of a proband (the technical term for the patient or individual who presents with a heritable disorder like Charcot-Marie-Tooth) and members of his or her family who also have the disease can allow scientists to pinpoint the genetic slips which cause disease.

In the paper, the investigators "identified a family with a recessive form of Charcot–Marie–Tooth disease for which the genetic basis had not been identified" or in other words, they took a case of disease whose genetic cause, slightly jumbled or abnormal DNA sequences, had not been identified.  They took parts of the proband's DNA that were likely to be implicated in the disorder from the entire sequenced genome and compared it to select pieces of genome from family members that also had disease symptoms.

This comparison between proband genetic code and family member genetic code allowed investigators to positively identify underlying genetic problem in this form of the disease.

This information can then be used for diagnosis and treatment planning of the condition in others.  As more associations of diseases (and even heritable factors which predispose people to diseases) with distinct genetic slips are made and technology to sequence and identify these slips becomes cheaper and more widespread, this technology will become commonplace in the provision of healthcare.  This has many exciting implications, as well as a few problematic ones.  As the editorial asks,

Who will benefit from comprehensive sequencing? When in a person's life should sequencing be done? How should we deal with the many variants of uncertain clinical significance? How should we interpret changes found outside of genes? How should we effectively communicate the results to patients in ways that will improve health without inducing neurosis?

Despite these serious concerns (which will doubtlessly be resolved as practitioners embrace the new methods), it is exciting to me to be learning the practice of medicine amidst scientific advances such as these.

One note:  Channeling University Diaries, one of my favorite education-related blogs, I caught this error in word choice from the editorial discussed above:  "The field has been driven by saltatory leaps in technology."

Saltatory (commonly used with the word 'conduction,' as in 'saltatory conduction,' to describe how an electrical signal travels in a certain type of nerves) means that the thing in question 'proceeds by leaps rather than by smooth, continuous variation."  Therefore to call something a 'saltatory leap' is redundant.  This is hardly a common mistake, but a mistake no less.

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