PCR haplotyping. (A) BS PCR products for subjects 75204 and 75205 using the 4qA DUX4 gene body primer set (left) or a primer set that non-specifically amplifies both 4qA and 10qA. BL: blood (PBMCs) and SA: saliva. (B) Genomic PCR amplification for either the 4qA or 4qB subtelomeres , as indicated. Although the 4qA D4Z4 gene body BS PCR did not produce a product for subject 75205 (No), standard PCR for 4qA alleles did produce a PCR product. These products were sequenced and confirmed as being 4C166H. These data together indicate that subject 75205 has a 4qB/C166H genotype. Additional predicted genotypes are indicated.