Single cell analysis demonstrating somatic mosaicism involving 11p in a patient with paternal isodisomy and Beckwith-Wiedemann syndrome.

Partial isodisomy of 11p has been observed in some patients with Beckwith-Wiedemann syndrome. In this study, we demonstrate somatic mosaicism directly through PCR and single cell analysis on blood lymphocytes from a patient with Beckwith-Wiedemann syndrome. Whole genome amplification was performed on single cells and the resultant product was subjected to locus specific microsatellite marker analysis using PCR. Two populations of cells were detected, a population of cells with normal biparental inheritance for chromosome 11 and a population of cells with partial paternal isodisomy of 11p between markers D11S922 (11p15.5) and D11S904 (11p14-p13). These results are consistent with somatic recombination resulting in mosaicism for paternal isodisomy. The use of single cell PCR is ideal for studying the distribution of mosaicism within and between tissues and has been used in this study to identify a cell line with uniparental disomy in a patient with Beckwith-Wiedemann syndrome.