PSPS1 is mutated in females with syndromic retinitis pigmentosa from a three-generation family. A. Pedigree of family RP-0482 and validation by Sanger sequencing of p.Ser16Pro demonstrating the correct segregation in the family. All affected individuals (II:2, III:2; IV:2 and IV:3) are heterozygous for the variant. Red circles indicate the individuals analysed by WES. Although II:2 and II:3 died during the course of the study, DNA samples and informed consents were obtained before deceasing, allowing us to include those subjects in the segregation analysis. B. Multiple sequence alignment of PRPS1 across species using ClustalW  confirms that p.Ser16 is identical from human to zebrafish. C. Schematic representation of PRPS1 with the location of the novel heterozygous mutation p.Ser16Pro in exon 1 (in red) and previously known mutations in Arts syndrome (in orange), PRS-I Superactivity (in green), Charcot-Marie-Tooth disease-5 (in blue), X-linked nonsyndromic sensorineural deafness (in purple), and also the recently reported mutation associated with retinal dystrophy (in brown). Exons are indicated by rectangles that are wider for the coding regions. Nucleotide numbering reflects cDNA in the reference sequence NM_002764. D. Model of PRS-I with p.Ser16Pro based on the crystal structure of human PRS-I (PDB: 2H06) and close-up of the mutation showing the loss of a hydrogen bound with residue Gln13. E. RT-PCR and sequencing analysis of p.Ser16Pro in mRNA. RNA was derived from peripheral blood lymphocytes of the three patients (IV:2, IV:3 and III:2) and an unaffected control (IV:1). Normally spliced amplicons of exons 1–2, 1–4 and 4–7 of PRPS1 comprising 229, 559 and 564 nucleotides, respectively, were found in all cases. Amplification of GAPDH mRNA analysis was used as positive control. Sanger sequencing of RT-PCR products evidences the absence of the wild-type allele in the cDNA of the proband (IV:3).