Below is an instruction from Human. Write a response.
    ### Instruction:
    Is thiopurine S-methyltransferase deficiency inherited ?
    ### Response:
    The activity of the TPMT enzyme is inherited in a pattern described as autosomal codominant. Codominance means that two different versions of the gene are active (expressed), and both versions influence the genetic trait.  The TPMT gene can be classified as either low-activity or high-activity.
    