1. ¹Section of Developmental Pharmacology and Experimental Therapeutics, Children's Mercy Hospital and Clinics, Kansas City, Missouri, USA
2. ²Genome Quebec and Montreal Heart Institute Pharmacogenomics Centre, Université de Montréal, Montreal, Quebec, Canada
3. ³Department of Psychiatry, Morehouse School of Medicine, Atlanta, Georgia, USA
4. ⁴Department of Medicine, Morehouse School of Medicine, Atlanta, Georgia, USA
5. ⁵Kosair Charities Pediatrics Clinical Research Unit, School of Medicine, University of Louisville, Louisville, Kentucky, USA

Correspondence: A Gaedigk, (agaedigk@cmh.edu)

Received 19 October 2006; Accepted 2 January 2007; Published online 28 March 2007.

Abstract

A 5-year-old African-American girl presented with a CYP2D6*4xN/*10 genotype that was discordant with her poor metabolizer phenotype determined with the probe drug dextromethorphan. Both phenotype and genotype were confirmed in repeat assessments, suggesting that the CYP2D6*10 allele carried a novel debilitating sequence variation(s). The rationale for this study was to resolve the discordance and to describe the novel non-functional allelic variant of CYP2D6 and its frequency in populations of different ethnic backgrounds.