Point mutations in exon 2 of the PIG-A gene in patient MSK13 before BMT. (A) Exon 2 of the PIG-A gene was first amplified by external primers -I₁ and I₂, and then reamplified with the internal primers (see Table 1). (B) Nt sequence of M13 clones containing exon 2 fragment of patient MSK13. All (G) reactions were loaded adjacent to each other, followed by the (A, T, and C) reactions. Two of the 3 M13 clones with substitution 211 T → C (clones 21, 22, 24) also have the 251 G → A substitution (clones 22 and 24).