Abnormal proliferation and spontaneous differentiation of myoblasts from a symptomatic female carrier of X-linked Emery-Dreifuss muscular dystrophy.

•X-linked female presenting with EDMD1 not explained by uneven X-inactivation.•First EDMD blood phenotype with highly lobulated lymphocytes in EDMD1 patient.•Found high incidence of spontaneous differentiation in cultured patient myoblasts.•Faster proliferation of emerin-null than emerin-positive EDMD1 patient myoblasts.•Loss of satellite cells from the above might explain EDMD pathology.