(A) Long PCR of genomic DNA using primers flanking exons 9 (9F ) and 13 (13R) of the GPIIIa gene. A normally amplified 15.9-kb fragment is seen in control DNA (WT) in the proband (P) and very faintly in her father (F ). An additional 4.7-kb fragment is seen in both the proband and her father. The λ DNA molecular weight marker cleaved with HindIII (M) is shown in the left lane. (B) Reamplification of the previous PCR products using reverse primer in exon 13 (M13R) and the same forward primer (9F ) shows more clearly the 15.9-kb fragment in the normal allele, in the proband (P), and in her father (F ).