Inconclusive Duchenne Muscular Dystrophy (DMD) carrier screening and atypical SNP-based NIPS sex chromosomes analysis suggest maternal sex chromosome abnormality

As of 2021, ACMG has expanded the recommended carrier screening panel to constitute 113 genes, now including the X-linked Duchenne Muscular Dystrophy (DMD) gene. Copy number variant (CNV) analysis by next-generation sequencing (NGS) of DMD yields inconclusive results for a small number of individuals due to the duplication/deletion of all DMD exons and adjacent regions on the X chromosome. In addition, a small number of SNP-based noninvasive prenatal screening (NIPS) tests yield no results for sex chromosomes due to a suspected maternal X chromosome abnormality.