Isodisomy is a non-mendelian trait in humans caused by both copies of a chromosomal set being inherited from the biological mother or the father. It differs from uniparental disomy in that instead of receiving an identical set of chromosomes from one parent, the fertilized ovum contains a complete set of chromosomes from one parent resulting in a complete set of chromosomes from only one parent. This may result in the expression of recessive traits in the offspring. Some authors use the term uniparental disomy and isodisomy interchangeably.
This genetic abnormality can result in the birth of a normal child who has no obvious disability. It is associated with abnormalities in the growth of the offspring and in the placenta.