Expression of 15q11-q13.1 genes in chromosome 15q11-q13.1 duplication syndrome (Dup15q) induced pluripotent stem cells (iPSCs) and iPSC-derived neurons. (a) Box plots depicting the distribution of average mRNA expression levels of 15q11-q13.1 genes in Dup15q iPSCs (top) and 10-week-old iPSC-derived neurons (bottom) relative to normal samples (Nml 1-0) as they correspond to the number of expressed copies of each gene. The dark gray line in the center of each box represents the median of the average relative mRNA expression levels of genes containing each number of expressed gene copies. Boxes indicate the 25th, 50th, and 75th percentiles. Whiskers represent the 5th and 95th percentiles. The data point for SNRPN in the pat. int dup(15)-04 iPSCs (marked by asterisk) is not indicative of unexpected mRNA expression levels relative to gene copy number, since this paternally expressed gene is duplicated on the paternal allele in this sample. (b) The average mRNA expression levels for selected 15q11-q13.1 genes in Dup15q iPSCs (top) and 10-week-old iPSC-derived neurons (bottom) relative to that of normal (Nml 1-0) iPSCs and neurons is presented in relation to the respective number of expressed copies of each gene.