OBJECTIVETo investigate the value of single nucleotide polymorphism array (SNP array) for the identification of de novo mutations in the DMD gene among fetuses.

METHODSG-banded karyotyping and SNP array were performed on a fetus with intrauterine growth restriction but without family history of Duchenne/Becker muscular dystrophy (DMD/BMD). Multiplex ligation-dependent probe amplification (MLPA) was subsequently applied on amniocytes and maternal peripheral blood sample to detect DMD gene deletion/duplication mutations.

RESULTSKaryotyping of amniocytes showed a normal 46, XY karyotype. SNP array on amniocytes detected a 116 kb deletion (chrX: 32 455 741-32 571 504) at Xp21.1 with breakpoints at introns 16 and 30 respectively, encompassing exons 17-29 of the DMD gene. In addition, MLPA analysis of the DMD gene on amniocytes confirmed the deletion of exons 17 to 29 identified by SNP array. However, no deletion/duplication mutation was detected by MLPA in the mother.

CONCLUSIONThe de novo deletion of exons 17 to 29 of the DMD gene detected in the fetus may result in BMD or DMD. SNP array can improve the efficiency for detecting genomic disorders in fetuses with unidentified pathogenic genes, negative family history and nonspecific phenotypes.