Identification of a 6-month-old baby with a combination of WAGR and Potocki-Shaffer contiguous deletion syndromes by SNP array testing

The Largest Germline Heterozygous Deletion Encompassing Potocki-Shaffer and WAGR Syndromes Loci to Date: A Case Report

Potocki-Schaffer syndrome includes multiple exostoses, parietal foramina, and variable developmental delay/intellectual disability. It is associated with a heterozygous deletion of the 11p12p11.2 region. In some cases, the deletion extends to the WAGR locus (11p13p12). We describe here a 9-month-old girl harboring the largest germline heterozygous deletion characterized so far. Oligohydramnios and parietal foramina were noticed during pregnancy. No patient has been diagnosed before with concomitance of these two syndromes during the prenatal period. Cytogenetic diagnosis was anticipated on basis of clinical and radiological signs. Postnatal conventional karyotype confirmed an interstitial 11p deletion: 46,XX,del(11)(p11.2p15.1). Array-comparative genomic hybridization characterized a 29.6 Mb deletion. Our case illustrates the interest of high-resolution genomic approaches to correlate adequately clinical phenotypes with specific genes in suspected contiguous gene deletion syndromes.

Characterization of Associated Nonclassical Phenotypes in Patients with Deletion in the WAGR Region Identified by Chromosomal Microarray: New Insights and Literature Review

WAGR syndrome (Wilms' tumor, aniridia, genitourinary changes, and intellectual disability) is a contiguous gene deletion syndrome characterized by the joint deletion of PAX6 and WT1 genes, located in the short arm of chromosome 11. However, most deletions include other genes, leading to multiple associated phenotypes. Therefore, understanding how genes deleted together can contribute to other clinical phenotypes is still considered a challenge. In order to establish genotype-phenotype correlation in patients with interstitial deletions of the short arm of chromosome 11, we selected 17 patients with deletions identified by chromosomal microarray analysis: 4 new subjects and 13 subjects previously described in the literature with detailed clinical data. Through the analysis of deleted regions and the phenotypic changes, it was possible to suggest the contribution of specific genes to several nonclassical phenotypes, contributing to the accuracy of clinical characterization of the syndrome and emphasizing the broad phenotypic spectrum found in the patients. This study reports the first patient with a PAX6 partial deletion who does not present any eye anomaly thus opening a new set of questions about the functional activity of PAX6.