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Imprinting carries an inherent genetic risk. Unlike normal diploid genes, in which the second copy can often function acceptably even if the first is lost to inherited or acquired mutation, imprinted genes behave as if they are haploid. A mutation in the lone active allele can result in complete loss of gene function. If the gene codes for a tumor suppressor, for example - and many imprinted genes are involved in cell growth and development - the result is cancer.