Figure 2
Detection of homozygous/hemizygous intragenic deletions and heterozygous deletions. (a) Top panel: the ratio of normalized mean coverage of individual coding exon of a gene to that of the reference was plotted against the exon number. The gray zone indicates the range of variation from the reference file. The individual’s value is colored in red. Bottom panel: the histogram of the ratio of normalized mean coverage of the same test sample. The x-axis for both the top and bottom panels are the corresponding exons in a gene. Homozygous deletions of exons 3–7 of MPV17 in patient (P) 1, homozygous deletion of a single exon 18 of LPIN1 in P2, and hemizygous deletion of exons 27–30 of PHKA2 on the X chromosome of an affected male patient (P3). (b) The corresponding array comparative genomic hybridization results are shown at the bottom panel of this figure. These known deletions are exons 4–8 of POLG2 in P4, exons 27–30 of PHKA2 in P5, exon 5 of ARG1 in P6, and exon 3 of SLC25A13 in P7. Massively parallel sequencing copy number variation analysis for P8, with heterozygous partial exonic deletion in OTC, is also shown. An atypical normalized coverage ratio of 0.7 suggests a heterozygous deletion of a partial exon.
