Genotype-phenotype correlations of pathogenic copy number variations on X chromosome detected by comparative genomic hybridization

Abstract

The aim of this study was to present genotype-phenotype correlations of pathogenic copy number variations (CNVs) on X chromosome. Clinical and microarray data of the cases were collected. Conventional cytogenetics and CytoSure 4×180K oligonucleotide array (Agilent Technologies, Inc.) (Comparative Genomic Hybridization - CGH) was applicated to all cases. Molecular and clinical characterisation of these CNVs was performed in this study. 18 cases were included in this study for having a pathogenic CNV on X chromosome. The changes were reported pathologically by evaluating break points, anomaly size, number of involved genes and their functions and phenotypic correlations. 16 cases with pathogenic CNVs of X chromosome were examined with the clinical findings of multiple congenital anomalies, mental retardation, eosophageal atresia, duodenal atresia, autism spectrum disorder, hypogonadotropic hypogonadism, dysmorphic features, muscular dystrophy, hydrocephaly, neuromotor growth retardation, trigonocephaly, high risk of prenatal screening test, recurrent pregnancy loss with reciprocal translocation, fetal loss with multiple congenital anomalies. 2 cases were diagnosed as Turner Syndrome with rare karyotypes and array-CGH results. Our study contributes to the genotype/phenotype correlation with the delineation of laboratory criteria which help to classify the different CNVs detected on X chromosome. Atypical microdeletions/duplications allowed us to define minimal critical regions that could be responsible for specific clinical findings of the syndromes and to highlight some genes.