Uniparental Disomy Studies

General testing for uniparental disomy (UPD) identifies UPD of the entire chromosome and does not address segmental UPD, mosaic UPD or UPD restricted to a certain tissue. Segmental UPD can be detected if markers are designed to address the specific region of interest, such as for the Angelman syndrome/Prader-Willi syndrome critical region on chromosome 15. This analysis can detect both uniparental heterodisomy and uniparental isodisomy for specific chromosomes. UPD studies can diagnose cases of uniparental disomy for various chromosomes (particularly chromosomes 6, 7, 14, and 15) or to conduct general microsatellite analysis for specific loci on a chromosome of interest. Analysis of microsatellite markers for mother, father and proband allow for the determination of inheritance of alleles as biparental, uninformative, or uniparental (maternal or paternal).

Indications for Testing

  • Structurally abnormal karyotype
  • Translocation involving chromosomes 6, 7, 14, or 15
  • Prenatal or postnatal mosaicism involving chromosomes 6, 7, 14 or 15
  • Confined placental mosaicism
  • Investigation of recessive disease
  • Transient neonatal diabetes
  • Russell-Silver syndrome
  • Prader-Willi or Angelman syndromes without a cytogenetic deletion
  • Unexplained intrauterine growth retardation
  • Patient with scoliosis, small hands and feet, short stature, developmental delay, precocious puberty, joint laxity, and macrocephaly (consistent with maternal UPD14).
  • Patient with polyhydramnios, small thorax, rib deformities, respiratory difficulty, facial anomalies, mental retardation (consistent with paternal UPD14)

Sample Requirements

Must receive at least two samples; at least one parent in addition to patient. We prefer to receive blood sample from each parent for best possible results.

  • Infants: 2 – 3 mL whole blood in purple top EDTA tube
  • Children (>2 years) and adults: 3 – 4 mL whole blood in purple top EDTA tube
  • Amniotic fluid or cultured amniocytes
  • Chorionic villi or cultured chorionic villi

Contact laboratory genetic counselors or molecular director for specific sample requirements in advance.

Note: Maternal blood sample is also required for Maternal Cell Contamination studies for prenatal samples. Send 3-4 mL purple top EDTA tube along with prenatal sample.

Sample Handling

Blood samples stored overnight should be refrigerated or kept cold. Blood samples should never be frozen. Specimens being sent from outside facilities should be packaged with a cold pack according to standard medical safety practices. The specimen should be shipped by overnight priority [scheduled to arrive by Friday morning at the latest].

Shipping Address

Center for Human Genetics Laboratory
10524 Euclid Avenue, Sixth Floor
Cleveland, OH 44106
216-983-1134

For local samples, please call Client Service (216-844-5227) to arrange for sample pick-up.

Turnaround Time

Three to nine days

CPT Code

81402

Please submit a completed Molecular Requisition (PDF) for each sample, including parents.