Genome sequencing and chromosomal microarray as a tool for evaluating phenotypic variability in individuals with X and Y chromosome variations

Aneuploidies of the X and Y chromosomes (XXY and XYY) are characterized by a high degree of phenotypic variability, particularly in regard to neurodevelopment. Individuals with these diagnoses have varying neurocognitive presentations ranging from neurotypical to frank intellectual disability. The source of this variability is not yet well understood and phenotypic predictions cannot be made on an individual basis. One layer of this variance could be explained by the presence of high-impact Mendelian disorders that may be co-occurrent in this population.