Molecular Genetic Testing
Uniparental Disomy (UPD1, UPD7, UPD14, UPD15)


Indication and Diagnostic Value

Uniparental disomy occurs when both chromosomes of the child have the same haplotype as the chromosome pair from one of the parents. In other words, the child carries either only the chromosomes from the father or from the mother. UPS has been observed for most chromosomes. UPD is the basis of a small number of well-defined clinical conditions including the following syndromes:

• Prader-Willi syndrome (UPD15)
• Angelman syndrome (UPD15)
• Beckwith-Wiedemann syndrome (UPD11)
• Silver-Russell syndrome (UPD7)
• Transient neonatal diabetes (UPD6)

The first three syndromes can also be due to other genetic causes (see respective Test Offers). In addition to he above conditions, certain other UPDs can be the cause of abnormality (intrauterine and postnatal growth retardation, intellectual deficit, congenital malformations, and dimorphic features).
Further indications for an UPD are a placental dysfunction due to mosicicism, finding of additional marker chromosomes or homologous translocations implying chromosomes 14 and 15.

Samples and Test Method

Uniparental disomy is demonstrated at the molecular level by using polymorphic markers to prove whether both chromosomes of the child have the same haplotype as one of the chromosomes from one of the parents (isodisomy), or the two chromosomes have he same haplotype as the chromosome pair from one of the parents (heterodisomy). To this end PCR fragments will be produced according to the microsatellite markers and genotyped by use of an ABI-Sequencer.
IMMD blood stain test paper is required.

Turnaround time for this test is 10 days.

→ list of Molecular Genetic Tests offered by IMMD


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