(a) Graphical overview of SNP-array (HumanCytoSNP-12 BeadChip) results regarding
chromosome 8, obtained with Genome Studio Data Analysis Software v.2008 (Illumina Inc.,
San Diego, CA, USA). Upper panel showing B-allele frequency demonstrates a long region
of homozigosity in the terminal region of the long arm of chromosome 8. The second panel
reports the Log R Ratio, indicating that no deletion is present in the same chromosome 8
region. (b) Electropherograms of sense strand sequence of TRAPPC9 exon
18 and flanking region. Nucleotide positions from 2851–7 to 2855 are shown.
Rectangles indicate the mutated nucleotide of the acceptor splice site (c.2851-2A>C).
(c) Electropherograms of TRAPPC9 cDNA direct sequencing. Upper panel:
patients' TRAPPC9 cDNA sequences, showing the complete absence of exon 18
from TRAPPC9 mature mRNA. Lower panel: parents' TRAPPC9 cDNA
sequences, demonstrating the simultaneous presence of both TRAPPC9 mature
transcripts containing and missing exon 18, respectively (peaks corresponding to the
longer transcript including exon 8 are lower than peaks from the shorter transcripts
probably due to PCR artifacts).