Improving molecular diagnosis of aniridia and WAGR syndrome using customized targeted array-based CGH.

Chromosomal deletions at 11p13 are a frequent cause of congenital Aniridia, a rare pan-ocular genetic disease, and of WAGR syndrome, accounting up to 30% of cases. First-tier genetic testing for newborn with aniridia, to detect 11p13 rearrangements, includes Multiplex Ligation-dependent Probe Amplification (MLPA) and karyotyping. However, neither of these approaches allow obtaining a complete picture of the high complexity of chromosomal deletions and breakpoints in aniridia. Here, we report the development and validation of a customized targeted array-based comparative genomic hybridization, so called WAGR-array, for comprehensive high-resolution analysis of CNV in the WAGR locus. Our approach increased the detection rate in a Spanish cohort of 38 patients with aniridia, WAGR syndrome and other related ocular malformations, allowing to characterize four undiagnosed aniridia cases, and to confirm MLPA findings in four additional patients. For all patients, breakpoints were accurately established and a contiguous deletion syndrome, involving a large number of genes, was identified in three patients. Moreover, we identified novel microdeletions affecting 3' PAX6 regulatory regions in three families with isolated aniridia. This tool represents a good strategy for the genetic diagnosis of aniridia and associated syndromes, allowing for a more accurate CNVs detection, as well as a better delineation of breakpoints. Our results underline the clinical importance of performing exhaustive and accurate analysis of chromosomal rearrangements for patients with aniridia, especially newborns and those without defects in PAX6 after diagnostic screening.

Ellis-van Creveld syndrome in a fetus with rhizomelia and polydactyly. Report of a case diagnosed by genetic analysis, and correlation with pathological andradiologic findings.

Ellis-van Creveld syndrome is an autosomal recessive disorder mainly characterized by a disproportionate limb dwarfism, chondroectodermal dysplasia, congenital heart disease, postaxial polydactyly, and dysplastic fingernails and teeth. Only 300 cases have been published worldwide. We report a 21-week fetus with rhizomelia and polydactyly detected. Gross photographs, radiologic studies and pathological study were performed leading to the clinico-pathological suspicion of EvC. DNA from fresh fetal tissue was extracted for sequencing the EVC and EVC2 genes. p.W215X and p.R677X mutations were identified in the EVC2 gene in the fetal sample. Parental sample analysis showed the p.W215X mutation to be inherited from the mother and the p.R677X mutation from the father. The clinical information is essential not only to arrive at a correct diagnosis in fetuses with pathologic ultrasound findings, but also to offer a proper genetic counseling to the parents and their relatives.