Copy number alterations at polymorphic loci may be acquired somatically in patients with myelodysplastic syndromes

Loss of genomic integrity is thought to be one of the underlying causes of myelodysplastic syndromes (MDS). However, it is unclear whether changes in copy number at loci that are common sites of copy number polymorphisms play a pathogenic role. Here we show that copy number changes in the MDS clone that occur at polymorphic loci are frequently somatic alterations rather than constitutional variants, and the extent of copy number changes at polymorphic loci is increased in CD34+ cells of MDS patients compared to age-matched controls. This study suggests a potential pathophysiological role for copy number alterations at polymorphic loci in patients with MDS, and highlights the need for somatic control tissues for each patient studied in high-resolution genome-wide investigations.