Effect of novel growth hormone receptor (GHR) variants on splicing. (A) Schematic showing the process of normal splicing of exons 8 and 9 of the GHR. (B) Schematic showing the process of alternative splicing of exons 8 and 9 of the GHR through the activation of a cryptic acceptor splice site in exon 9. (C) Gel electrophoresis of polymerase chain reaction (PCR) cDNA splicing products from GHR exon trap assays. Lane 1: 250 bp empty vector (EV), representing the 2 exons of the exon trap (ET) vector. Lane 2: 320 bp wildtype sequence (WT), representing the 2 exon trap vector exons (250 bp) and normally spliced GHR exon 9 (70bps). Lanes 3 and 4: A smaller 294 bp band was detected in both probands consistent with the mutant GHR exon 9, which leads to a frameshift (confirmed by Sanger sequencing). Proband 1 has WT cDNA present, and proband 2 predominantly has mutant cDNA.