Targeted 'Next-Generation' sequencing in anophthalmia and microphthalmia patients confirms SOX2, OTX2 and FOXE3 mutations

<p>Abstract</p> <p>Background</p> <p>Anophthalmia/microphthalmia (A/M) is caused by mutations in several different transcription factors, but mutations in each causative gene are relatively rare, emphasizing the need for a testing approach that screens multiple genes simultaneously. We used next-generation sequencing to screen 15 A/M patients for mutations in 9 pathogenic genes to evaluate this technology for screening in A/M.</p> <p>Methods</p> <p>We used a pooled sequencing design, together with custom single nucleotide polymorphism (SNP) calling software. We verified predicted sequence alterations using Sanger sequencing.</p> <p>Results</p> <p>We verified three mutations - c.542delC in S<it>OX2</it>, resulting in p.Pro181Argfs*22, p.Glu105X in <it>OTX2 </it>and p.Cys240X in <it>FOXE3</it>. We found several novel sequence alterations and SNPs that were likely to be non-pathogenic - p.Glu42Lys in <it>CRYBA4</it>, p.Val201Met in <it>FOXE3 </it>and p.Asp291Asn in <it>VSX2</it>. Our analysis methodology gave one false positive result comprising a mutation in <it>PAX6 </it>(c.1268A > T, predicting p.X423LeuextX*15) that was not verified by Sanger sequencing. We also failed to detect one 20 base pair (bp) deletion and one 3 bp duplication in <it>SOX2</it>.</p> <p>Conclusions</p> <p>Our results demonstrated the power of next-generation sequencing with pooled sample groups for the rapid screening of candidate genes for A/M as we were correctly able to identify disease-causing mutations. However, next-generation sequencing was less useful for small, intragenic deletions and duplications. We did not find mutations in 10/15 patients and conclude that there is a need for further gene discovery in A/M.</p

The Epidemiology, Genetics and Future Management of Syndactyly

Syndactyly is a condition well documented in current literature due to it being the most common congenital hand defect, with a large aesthetic and functional significance

Mutation of the gene encoding the ROR2 tyrosine kinase causes autosomal recessive Robinow syndrome

Robinow syndrome is a short-limbed dwarfism characterized by abnormal morphogenesis of the face and external genitalia, and vertebral segmentation(1,2). The recessive form of Robinow syndrome (RRS; OMIM 268310). particularly frequent in Turkey(3-6), has a high incidence of abnormalities of the vertebral column such as hemivertebrae and rib fusions. which is not seen in the dominant form. Some patients have cardiac malformations or facial clefting. We have mapped a gene for RRS to 9q21-q23 in 11 families. Haplotype sharing was observed between three families from Turkey, which localized the gene to a 4.9-cM interval. The gene ROR2, which encodes an orphan membrane-bound tyrosine kinase, maps to this region. Heterozygous (presumed gain of function) mutations in ROR2 were previously shown to cause dominant brachydactyly type B (BDB; ref. 7). In contrast, Ror2(-/-) mice have a short-limbed phenotype that is more reminiscent of the mesomelic shortening observed in RRS. We detected several homozygous ROR2 mutations in our cohort of RRS patients that are located upstream from those previously found in BDB. The ROR2 mutations present in RRS result in premature stop codons and predict nonfunctional proteins

Physical and transcript map of the autosomal dominant colobomatous microphthalmia locus on chromosome 15q12-q15 and refinement to a 4.4 Mb region.

International audienceCongenital microphthalmia is a developmental disorder characterized by shortened axial length of the eye. We have previously mapped the gene responsible for autosomal dominant colobomatous microphthalmia in a 5-generation family to chromosome 15q12-q15. Here, we set up a physical and transcript map of the 13.8 cM critical region, flanked by loci D15S1002 and D15S1040. Physical mapping and genetic linkage analysis using 20 novel polymorphic markers allowed the refinement of the disease locus to two intervals in close vicinity, namely a centromeric interval, bounded by microsatellite DNA markers m3-m17, and a telomeric interval, m76-m24, encompassing respectively 1.9 and 2.5 Mb. Moreover, we excluded three candidate genes, CKTSF1B1, KLF13 and CX36. Finally, although a phenomenon of anticipation was suggested by phenotypic and pedigree data, no abnormal expansion of three trinucleotide repeats mapping to the refine interval was found in affected individuals