Fig. 1

a Pedigree of the family showing the affected proband (arrow), homozygous for the c.702 + 1del variant in the BBS9 gene, and his heterozygous (carrier) parents. The three siblings of the proband have not been tested (nt: not tested). b, c DNA sequencing of proband with NGS (b) and subsequent validation with Sanger (c) showing the novel gene variation identified, c.702 + 1del variant affecting the first base of intron 7–8 (arrow). d Microfluidic technology after RT-PCR using primers located in exons 6 and 8. A band of 245 bp corresponding to the wild-type (Wt) gene and a band of 157 bp corresponding to the variant lacking exon 7 is shown in the heterozygous parents (I.1 and I.2) while only the variant form is seen in the homozygous proband (II.2). e Sanger sequencing of the splicing variant resulting from the skipping of the whole exon 7. f Interpretation of the empirical observations combining the results of RT-PCR and Sanger sequencing from both Wt and c.702 + 1del alelles