Mixture model

Colleagues I am analyzing data in which there are two distinct populations as a result of CYP2D6 deficiency. In one dataset, there are 18 subjects with rich data; one of these subjects is markedly different. In that the incidence of 2D6 deficiency is reported to be < 10%, one would expect only 1-2 deficient subjects in this sample (consistent with the data here). I was planning to use a mixture model as part of the analysis. However, with only one subject in the deficient population, I am not sure if that is appropriate. Does anyone have any relevant experience or insight into this issue? Dennis Dennis Fisher MD P < (The "P Less Than" Company) Phone: 1-866-PLessThan (1-866-753-7784) Fax: 1-866-PLessThan (1-866-753-7784) www.PLessThan.com