Recent Developments in Diagnosis and Care for Girls in Turner Syndrome

Figure 1

Xp deletion in a patient with BAV and aortic coarctation. The breakpoint is at X p11.4 and ChX 41,500,000 shown by array comparative genomic hybridization (aCGH). The break interrupts the gene CASK between the eighth and ninth exons. In this type of array analysis, genomic DNA from controls (reference sample) is labeled with one color dye, while gDNA from the test subject is labeled with a dye of a different color. The labeled test and reference samples are mixed together, denatured, and allowed to hybridize to the microarray which contains DNA probes. In this case we used high-resolution custom X chromosome tiling arrays containing 220,000 probes with average 280 bp spacing (Agilent Technology). Only theX chromosome short arm (Xp) is illustrated here, with pter at the extreme left and centromere to the right. The presence of competitive hybridization from both reference and test samples is obvious up until ChX 41,500,000, where the test signal completely disappears, indicating the Xp deletion at that locus. The figure is adapted from [11].