Fig. 3

Genomic sequencing and RT-PCR of mRNA transcripts. a Genomic DNA sequencing of exon 4 (father) and intron 5 (mother) showing the nonsense mutation (c.192G > A p.W64X) in exon 4, and the splicing mutation (c.441-24A > G) in intron 5. b RT PCR from cDNA exon 3 to 7. An alternative transcript without exon 6 exists in all subjects. c The domains of the DHDDS protein that contain the isopentenyl diphosphate (IPP) and farnesyl diphosphate (FPP) binding sites are indicated along with the region containing the active site (vertical bar). The mutation seen in the father leads to a mRNA containing a premature stop codon which if translated would lead to a severely truncated protein (W64X) missing the IPP binding site. Translation of the mother’s variant mRNA would lead to a severely truncated protein (p.Cys148GlufsX11) containing 11 new amino acids (grey box) before the stop codon