DMD germline mosaic mutation and genetic counseling in a mother of a patient with Duchenne muscular dystrophy

Abstract

  Duchenne muscular dystrophy (DMD) is one of the serious muscular diseases that occurs in 1 in 3,500 male births. The responsible gene, DMD, is located at Xp21 and thus related to an X-linked recessive inheritance pattern. Many patients inherit mutations from their mother who are DMD mutation carriers ; however, in sporadic cases without positive family histories, genetic testing is necessary to clarify whether the mothers are carriers or not. Although the proband's mother longed for the next child, she could not think positively about carrier diagnosis. Therefore, we spent enough time for genetic counseling. In this study, we identified a rare germline mosaicism of [NM_004006.2 (DMD) : c.1132C>T (p.Gln378^＊)] in the proband's mother, and evaluated the risk of recurrence based on the mosaic ratio in the tissues other than the blood. Later, she understands and accepts her own situation more objectively by thinking about the result and considering rare mosaic mutations.