Ocular phenotypic characteristics of patient IV-7.

<p>Spectral domain optic coherence tomography (SD-OCT) of the left eye shows a normal foveal contour (A).Fundus photographies show discreet palor of the optic nerve (<b>B</b>) and irregular pigmentation in the macular area (<b>C</b>). Ocular phenotypic characteristics of patient IV-8: Spectral domain optic coherence tomography (SD-OCT) of the left eye shows a normal foveal contour (<b>D</b>). Fundus photographies show discreet palor of the optic nerve (<b>E</b>) and irregular pigmentation in the macular area especially in the right eye (<b>F</b>). Ocular phenotypic characteristics of patient III-5: Fundus fluorescence and indocyanine green angiography of the left eye show no leakage (<b>G</b>, <b>H</b>). Fundus photographies show myopic changes: posterior staphyloma, lacquer cracks, Fuchs’ spot of the macula and chorioretinal and parapapillary atrophy (<b>I</b>). Electrophysiologic examination (<b>J</b>): Full-field ERG shows normal scotopic and photopic answers in the female carrier (III-6). In the school boy (IV-7) ERG showed slightly reduced scotopic a- and b-waves with photopic answers below noise level. In the two adults (III-5, II-8), scotopic a- and b-waves were severely reduced with non-recordable photopic ERG.</p

Graphical representation of <i>CACNA1F</i> NGS coverage (exons 14 to 35) for individual III-6 (conductor) versus pooled DNA samples derived from affected males.

<p>The genomic structure of <i>CACNA1F</i> (exons 14-35) is shown below. NGS coverage data suggest reduced signals of the <i>CACNA1F</i> exons 18-26 for individual III-6 while signals for those exons are absent in the pooled DNA sample (<b>A</b>). Analysis of genomic DNA shows junction fragment PCR-products only in patients and carriers but not in controls (<b>B</b>). Exons 18-26 were absent in all patients tested. NTC = no template control. Sequencing of the junction fragment product revealed breakpoints within two AluSx repeats located in intron 17 and 26 (<b>C</b>).</p

Pedigree of the family compatible with an x-linked recessive mode of inheritance.

<p>Four of the 10 affected males (IV-7, IV-8, III-5 and II-8) and two female carriers (III-6 and III-9) have been examined.</p

Analysis of cDNA derived from EBV-transformed lymphoblastoid cell lines (LCLs) of individuals IV-7 (affected), III-6 (female carrier) and II-5 (affected) shows expression of the truncated transcript in all samples while the WT-transcript was present only in the female carrier and the positive control (Human Retina Marathon-Ready™ cDNA).

<p>NTC = no template control.</p

Mutation ofPOC1Bina severe syndromic retinal ciliopathy

We describe a consanguineous Iraqi family with Leber congenital amaurosis (LCA),Joubert syndrome (JBTS), and polycystic kidney disease. Targeted NGS for excluding mutations in known LCA and JBTS genes, homozygosity mapping and whole-exome sequencing identified a homozygous missense variant, c.317G>C (p.Arg106Pro), in POC1B,a gene essential for ciliogenesis, basal body and centrosome integrity. Insilico modeling suggested a requirement of p.Arg106for formation of the third WD40 repeat and a protein interaction interface. In human and mouse retina, POC1B localized to the basal body and centriole adjacent to the connecting cilium of photoreceptors and in synapses of the outer plexiform layer. Knockdown of Poc1b in zebrafish caused cystic kidneys and retinal degeneration with shortened and reduced photoreceptor connecting cilia, compatible with the human syndromic ciliopathy. A recent study describes homozygosity for p.Arg106Pro[subscript POC1]B in a family with non-syndromic cone-rod dystrophy. The phenotype associated with homozygous p.Arg106Pro[subscript POC1]B may thus be highly variable, analogous to homozygous p.Leu710Ser inWDR19 causing either isolated retinitis pigmentosa or Jeune syndrome. Our study indicates that POC1B is required for retinal integrity, and we propose POC1B mutations as a probable cause for JBTS with severe polycystic kidney disease