(C) Schematics of normal BET1 exon 3-4 splicing (top) and the various aberrant splice products associated with the paternally inherited p.(Asp68His) variant in P1. Splice variant one utilizes normal splicing generating a full-length BET1 protein with the Asp68His substitution. Splice variant two skips exon 4 to non-coding transcript (NR_133908) exon 5, resulting in a shift of the reading frame and a premature termination codon after 18 amino acids. Splice variant three utilizes a cryptic splice acceptor within exon 4, deleting the first 34 nucleotides of exon 4, and producing again a frameshift and a premature termination. The maternally inherited frameshift variant c.134delC introduces a premature stop codon in exon 2 and is predicted to induce nonsense mediated decay (NMD). 