A fluorescent method for detecting low-grade 11patUPD mosaicism in Beckwith-Wiedemann syndrome.
The quantitative evaluation of mosaicism for uniparental disomy (UPD) involving a restricted chromosomal region requires the availability of a sensitive and reproducible method that is capable of detecting even a small percentage of disomic cells and avoiding false positive and false negative results. The occurrence of UPD is usually monitored by means of the parent-proband segregation analysis of microsatellites mapping to the target region. We here describe the quantitative blood cell evaluation of segmental mosaic UPD11, a marker of Beckwith-Wiedemann syndrome, by means of the segregation analysis of 11p15 microsatellites using both radioactive and fluorescence-based techniques. As the greater amplification efficiency of the shorter allele in heterozygous subjects may bias the correct evaluation of disomy, the mean short/long allele ratio was established at three loci of each of 30 normal heterozygous subjects, as well as the peak As/Al area in the presence of 50% of each allele. The interval was defined using a 5% level of significance. The results show that the fluorescence-based technique is superior to radioactivity in detecting the subtle allelic imbalances present in low-grade mosaicism conditions.
Russo
Silvia
S
Laboratory of Molecular Biology, Istituto Auxologico Italiano, Milan 20135, Italy. s.russo@auxologico.it
Mencarelli
Monica
M
Cavalleri
Florinda
F
Selicorni
Angelo
A
Cogliati
Francesca
F
Larizza
Lidia
L
D000483:Alleles; D001506:Beckwith-Wiedemann Syndrome / Q000235:genetics*; D002880:Chromosomes, Human, Pair 11; D005456:Fluorescent Dyes; D018392:Genomic Imprinting / Q000235:genetics; D006801:Humans; D007553:Isotope Labeling; D018895:Microsatellite Repeats / Q000235:genetics*; D009030:Mosaicism / Q000235:genetics*; D024182:Uniparental Disomy / Q000235:genetics*
D005456:Fluorescent Dyes