Isoniazid‐induced polyneuropathy in a tuberculosis patient – implication for individual risk stratification with genotyping?
Mark Stettner1 
Daniela Steinberger2 
Christian J. Hartmann1 
Tatjana Pabst2 
Lidija Konta2 
Hans Peter Hartung1 
[1] Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany;bio.logis Center for Human Genetics, Frankfurter Innovationszentrum Biotechnologie (FIZ), Frankfurt am Main, Germany
Development of polyneuropathy (PNP) under treatment for tuberculosis (TB), including isoniazid (INH), is a highly relevant adverse drug effect. The NAT2 acetylation status is a predictor of potential toxic effects of INH. The question as to whether individual risk stratification by genotyping is useful to avoid suffering of patients and to lower costs for the health care system is of considerable clinical importance.
Case Presentation
After drug treatment for TB, including INH, a 23-year-old man developed severe PNP. During the treatment, laboratory results have been indicating incipient liver and renal injury. Later, molecular genetic analyses were performed and revealed a variation in the NAT2 gene and the c1/c2 genotype of the CYP2E1 gene, both described to contribute to an elevated risk for anti-tuberculostatic-induced liver damages (ATIL).
Conclusion
The combination of metabolizer genotypes should be taken into account as a cause for toxic effects and the development of PNP. Individual genotyping, performed before medication or at least if an elevation of liver parameters is observed, may reduce the risk of severe cases of PNP by early adjustment of treatment. Our case study indicates that evaluation of individual risk stratification with systematic pharmacogenetic genotyping of metabolizer gene combinations in the context of TB treatment should be addressed in clinical studies with larger cohorts.