Microdeletions in band 15q15.1 involving the MGA locus. (A) Inferred log2-ratio of SNP copy number data on chromosome 15q (median smoothing with a window of 5 consecutive markers; losses are indicated in blue, gains in red). Eight deletions are covering the MGA locus, the other 5 are located in close vicinity to a maximum distance of 1.373 Mb. (B) Raw log-ratio, chromosome 15 (case number CLL252up) displayed with the UCSC genome browser (hg18). Red bars represent the determined log2 ratio of single probe sets sorted by their physical position along the chromosome. Shown is the smallest deletion on 15q15.1 within the MGA locus, 70.48 kb in size. (C) Forward and reverse sequence analysis of exon 17 revealing a subclonal nucleotide exchange C → T in position 6143 that codes for a premature stop codon in case number CLL036. This sequence variation was not detectable in the nontumor reference sample (case number CLL036pn) and in a follow-up sample taken after treatment (case number CLL036fu).