John L. Black, M.D.

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SUMMARY

John Logan Black, M.D., is co-director of the Personalized Genomics Laboratory in the Department of Laboratory Medicine and Pathology and is jointly appointed to the Department of Psychiatry and Psychology. Much of Dr. Black's research has laid the foundation for treatment techniques that are now part of clinical practice.

Focus areas

• Psychiatry. Dr. Black's early career linked basic science research in neuroreceptor binding to drug side effects in clinical psychiatry. At the time that this research was conducted, little was known about the etiology of side effects caused by psychotropic medications. This body of work provided a clinical interpretation of the basic research conducted by Elliott Richelson, M.D., with Mayo Clinic, and provided a scientific basis for drug selection to avoid common side effects.
• Autoimmunity. Dr. Black has examined the role of autoimmunity in tardive dyskinesia, stiff man syndrome, Lambert-Eaton myasthenic syndrome and narcolepsy. This body of work was aimed at defining the neuronal autoimmune etiology of a variety of paraneoplastic and non-paraneoplastic conditions. The work on Lambert-Eaton myasthenic syndrome, which is associated with small cell lung cancer, was designed to seek the epitope for the condition using human P/Q-type calcium channel alpha 1 subunit components that he had successfully cloned. The work related to narcolepsy focused on evaluating hypocretin (orexin) neurotransmission-related proteins as well as other neuron-specific and non-neuron-specific antibodies as potential autoimmune targets in individuals with narcolepsy.

• Clinical genotyping. Dr. Black discovered several members of the human neuronal voltage-gated calcium channel (VGCG) gamma subunit family. At the time of this research, the human genome project was beginning to make human genome sequence data available. Muscle-type calcium channels were known to have an associated gamma subunit, but none of the many neuronal and cardiac calcium channels' gamma subunits had been discovered. By capitalizing on data from The Jackson Laboratory, Dr. Black was able to identify and clone the VGCC gamma subunits 2, 3 and 4. This pivotal work led to rapid expansion of knowledge about these subunits and the discovery that they are associated not only with VGCC but also are associated with alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) glutamate receptors.

  Dr. Black defined variations in the CYP2D locus in humans and developed and commercialized clinical testing methodologies for this and other complex genotyping problems. CYP2D6 enzyme metabolizes a large percentage of drugs in use today, but it is a highly complex gene due to the presence of duplications, multiplications, deletions and hybrid alleles with its pseudogene, CYP2D7. His original work defined several CYP2D6 hybrid alleles and the CYP2D locus. This background knowledge was used to generate clinical tests that are in use at Mayo Clinic to provide definitive genotyping of this gene.

• Drug selection algorithms. The Personalized Genomics Laboratory does clinical grade pharmacogenomic genotyping for clinical and research patients. Dr. Black has designed algorithms used to select medications based upon an individual's genotype and has generated algorithms that can make copy number variation determinations for genes such as CYP2D6 using next generation sequencing data. He has designed and clinically implemented many genotyping assays for pharmacogenes including the CYP2D6 genotyping cascade, which deals with the complexities this gene presents in the clinical and research setting.

  Dr. Black was involved in generating the first pharmacogenomic selection algorithm for psychotropics. One problem with implementing pharmacogenomics in clinical practice is that interpretation of results exceeds the abilities of most clinicians. Dr. Black collaborated to generate a five-gene algorithm for psychotropic selection in 2006, which has been adopted for clinical use. Subsequently, Dr. Black has worked with other collaborators to develop drug selection algorithms for the rest of the drugs in the pharmacopeia, which have also been used in clinical practice.

Significance to patient care

Dr. Black's primary research focus yields findings that will allow more accurate drug selection and dosing based upon an individual's genotype. Ultimately, this will improve the patient's overall treatment and outcome.

Professional highlights

• Recipient, Minnesota Medical Association Service Award, 2006
• Education award, American College of Psychiatrists, 2005
• Distinguished fellow, American Psychiatric Association, 2003