Mutation analysis of the SGCG gene in patient 2. Capillary electrophoretic patterns of the PCR products are shown in the upper portion of the figure. Five genomic regions were co-amplified in one PCR reaction, with the products separated using capillary electrophoresis. The position of each of the amplified products of exons 5, 6, 7, and 8 of the SGCG gene and exon 2 of the α-dystroglycan gene (DG) are marked. In patient 2, the peak area of exon 6 is nearly half that of the control, indicating a heterozygous deletion of exon 6. IS refers to a 1,500-bp marker. The amplified fragments that encompassed exons 5 to 8 of the SGCG mRNA are shown in the lower part of the figure (c; control, p; patient). Two different product sizes were obtained from the patient. Sequencing of the products disclosed that one exhibited a complete absence of exon 6, while the other included a nucleotide insertion in exon 7 (c.602_603insT). Thus, in this patient there was both a heterozygous nucleotide insertion in exon 7 and a heterozygous deletion of exon 6 of the SGCG gene.