A novel heterozygous mutation (c.325dup) was identified in EXT1 gene from the proband and the affected family members; this mutation was absent in all the unaffected family members. The identification of the novel frameshift insertion mutation (c.325dup) expands the mutation spectrum of HME, which provides new evidence for HME diagnosis.

The Duchenne Muscular Dystrophy (DMD) gene variants are associated with the disease phenotypes. The pathogenic mutation, c.2293-1G>C, was detected in DMD gene in the proband and the fetus, which has not been reported in the literature.The minigene expression in vitro confirmed that c.2293-1G>C is responsible of aberrant splicing.