What is uniparental disomy, and what conditions can result from it?

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What is uniparental disomy, and what conditions can result from it?

Uniparental disomy means both copies of a chromosome come from the same parent rather than one from each parent. Because many genes are expressed depending on whether they’re inherited from the mother or the father (imprinting), having two copies from one parent can disrupt normal gene expression and lead to imprinting disorders. For chromosome 15, this can cause Angelman syndrome if both copies are paternal, or Prader-Willi syndrome if both copies are maternal. In addition, uniparental disomy can reveal recessive diseases by making the child homozygous for a mutation carried by that parent. The other described chromosomal changes are different mechanisms: translocation is a rearrangement between chromosomes, duplication is an extra copy of a chromosome segment, and missing a chromosome is monosomy.

Uniparental disomy means both copies of a chromosome come from the same parent rather than one from each parent. Because many genes are expressed depending on whether they’re inherited from the mother or the father (imprinting), having two copies from one parent can disrupt normal gene expression and lead to imprinting disorders. For chromosome 15, this can cause Angelman syndrome if both copies are paternal, or Prader-Willi syndrome if both copies are maternal. In addition, uniparental disomy can reveal recessive diseases by making the child homozygous for a mutation carried by that parent. The other described chromosomal changes are different mechanisms: translocation is a rearrangement between chromosomes, duplication is an extra copy of a chromosome segment, and missing a chromosome is monosomy.

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