Uniparental disomy (UPD) of chromosome 6 describes a condition in which both homologs of chromosome 6 are derived from the same parent. Paternal UPD6 (UPD6pat) has been demonstrated in individuals with transient neonatal diabetes mellitus. UPD6 testing is therefore often considered when hypomethylation is identified with methylation specific-MLPA of 6q24.  

Maternal UPD6 is rare and intrauterine growth restriction (IUGR) appears to be the most common phenotype observed. UPD6 studies may also be appropriate to investigate the detection of mosaic trisomy 6 or a marker 6 chromosome in a prenatal sample or to rule out and unbalanced translocation. 

The UPD6 test compares microsatellite markers in samples from the proband and maternal and paternal samples. In order for UPD to be determined, a significant number of informative microsatellite markers must be present. Although testing is possible if only one parent is available, the chance of obtaining a sufficient number of informative markers is decreased.  

2 - 4 weeks
CPT Code 
Test Code 
Test Methods 
Microsatellite analysis
Specimen Types Accepted 
Cultured Cells
Extracted DNA
Additional Information 
The cost for prenatal UPD is $740