Incidental finding of a DMD exons 48-55 deletion during prenatal diagnosis

Min Zhang ¹ Zhaodong Lin ² Meihuan Chen ¹ Danhua Guo ¹ Qiaomei Yang ³ Qianqian He ¹ Bin Mao ¹ Bin Liang ¹ Lingji Chen ¹ Meiying Cai ^1* Hailong Huang ^1* Liangpu Xu ^1*

• ¹ Fujian Provincial Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Provincial Maternity and Children's Hospital, Fuzhou, China
• ² Department of Clinical Laboratory, Fuzhou First General Hospital, Fuzhou, 350009, Fujian Province, China, Fuzhou, China
• ³ Department of Gynecology, Fujian Maternity and Child Health Hospital, Fuzhou, China

Background DMD genetic variants cause a spectrum of phenotypes, from severe progressive proximal muscle weakness and degeneration leading to wheelchair dependence and death from cardiac and/or respiratory failure to very mild muscular phenotypes; very rarely, cases are completely asymptomatic. Few cases have been reported in males carrying DMD deletions who are asymptomatic. Methods Family clinical information was collected from the patients. A single nucleotide polymorphism array (SNP-array) was used to detect abnormalities in prenatal diagnosis, and multiplex ligation-dependent probe amplification (MLPA) and long-read sequencing (LRS) were used to confirm the detected variant. Results We incidentally identified DMD exons 48-55 deletion using SNP-array in prenatal diagnosis; the variant was confirmed using MLPA and LRS, and the fragment size and precise locations of breakpoints were determined. The variant was precisely located at genomic position chrX:31640088-31945085, spanning from intron 47 to intron 56 in DMD. Serum biochemical indicators were normal in the male with the deletion. Conclusion Our study is the first to report a DMD exons 48-55 deletion in prenatal diagnosis. The phenotypes of DMD variants are diverse, and this study suggests that prediction of clinical severity based solely on molecular findings should be interpreted with caution.