Pluripotency for all iPSC lines was confirmed by immunocytochemistry using antibodies (Ab) against Tra-1-60, Tra-1-81, SSEA3 and SSEA4, which are expressed in pluripotent stem cells. In addition, the capacity to differentiate into all 3 germ layers was established by in vitro assays, as previously described [24, 35]. The markers desmin (mesoderm), α-fetoprotein (endoderm), and βIII-tubulin (ectoderm) were used [22, 37, 38]. A list of the antibodies used to evaluate the iPSCs can be found in Additional file 2. Karyotyping was carried out by Cell Line Genetics (Madison WI). Each iPSC line used in this study had a normal karyotype, but each patient harbors the large, ~3 Mb deletion on 22q11.2, which was identified by FISH using a TUPLE probe or microarray [34].
