Prenatal diagnosis for a Chinese family with a de novo DMD gene mutation: A case report.BACKGROUND
 Patients with Duchenne muscular dystrophy (DMD) usually have severe and fatal symptoms.  At present, there is no effective treatment for DMD, thus it is very important to avoid the birth of children with DMD by effective prenatal diagnosis.  We identified a de novo DMD gene mutation in a Chinese family, and make a prenatal diagnosis.


 First, multiplex ligation-dependent probe amplification (MLPA) was applied to analyze DMD gene exon deletion/duplication in all family members.  The coding sequences of 79 exons in DMD gene were analyzed by Sanger sequencing in the patient; and then according to DMD gene exon mutation in the patient, DMD gene sequencing was performed in the family members.  On the basis of results above, the pathogenic mutation in DMD gene was identified.


 MLPA showed no DMD gene exon deletion/duplication in all family members.  Sanger sequencing revealed c.2767_2767delT [p.Ser923LeufsX26] mutation in DMD gene of the patient.  Heterozygous deletion mutation (T/-) at this locus was observed in the pregnant woman and her mother and younger sister.  The analyses of amniotic fluid samples indicated negative Y chromosome sex-determining gene, no DMD gene exon deletion/duplication, no mutations at c.2767 locus, and the inherited maternal X chromosome different from that of the patient.


 CONCLUSION
 The pathogenic mutation in DMD gene, c.2767_2767delT [p.Ser923LeufsX26], identified in this family is a de novo mutation.  On the basis of specific conditions, it is necessary to select suitable methods to make prenatal diagnosis more effective, accurate, and economic.
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