Co-occurrence of Xp21 microduplication encompassing the DMD locus in conjunction with 17p12/PMP22 microduplication in a female with Charcot–Marie–Tooth disease type 1A

Abstract

We report on the molecular detection of two microduplications involving chromosomes Xp21.1–Xp21.2 and 17p12 in a 35-year-old female with clinical phenotype of Charcot–Marie–Tooth disease type 1A (CMT1A) documented by chromosomal microarray analysis. The 17p12 microduplication was approximately 1.32Mb in size and contained eleven genes including the peripheral myelin protein 22 (PMP22), while the Xp21.1–Xp21.2 microduplication was estimated to be 626Kb in size and contained part of the dystrophin (DMD) gene. Constitutional interstitial microduplication of 17p12 segment encompassing the PMP22 gene has been reported in individuals with Charcot–Marie–Tooth disease type 1A. Defects in the DMD gene (deletion, duplication, or mutation) are associated with Duchenne and Becker muscular dystrophies (DMD and BMD). Combined microduplications of Xp21/DMD with 17p12/PMP22 are extremely rare with only one published report of a male patient with changes in both the DMD and PMP22 genes.