Nontraditional inheritance.

It has become clear in recent years that not all forms of inheritance follow classical mendelian laws regarding the equal contribution from both parents. These nontraditional modes of inheritance and gene expression include cytoplasmic inheritance, mosaicism, uniparental disomy, and genomic imprinting. All of these have been implicated in human genetic disorders and cancers and thus need to be kept in mind when trying to understand unusual observations in the clinic as well as when providing genetic counseling.