Uniparental Disomy

UPD is the presence of two paternal or two maternal chromosomes and the lack of the alternate parental chromosome, which may reveal gene or genes having genomic imprinting effects or cause the expression of an autosomal recessive gene or genes. If the parent has contributed one copy of each chromosome, it is termed heterodisomy. Genomic imprinting is, simply to say, the genes inherited from the mother, while identical in DNA sequence to those inherited from the father, do not function interchangeably. Genomic imprinting may cause a developmental imbalance due to the expression of one rather than two genes. If a parent has contributed two copies of one chromosome it is termed isodisomy. It could also imply the presence of two identical mutated genes if it is isodisomy.

UPD studies can be performed for all chromosomes.

Methodology:Polymerase Chain Reaction (PCR)/Microsatellite markers on the chromosome of interest are used to test DNA from parents and child for the presence of uniparental disomy.

Purpose: Evaluation of patients presenting with mosaicism, or Robertsonian translocations. Evaluation of patients presenting with features of disorders known to be associated with uniparental disomy (eg, Russell-Silver syndrome).

Test Requisition: Molecular Requisition

CPT Code: 81402 Cost: $365.00

Turn-around-time: 3 weeks