Detection of IVS4 mutation by PCR-SSCP and subsequent direct sequencing.

(A) Representative PCR-SSCP analyses using the primer set for exon 4 boundaries. 4510C cells are homozygous for the IVS4 mutation; FA239 cells are heterozygous (IVS4/wt) for this segment; and N indicates normal control. The patient numbers correspond to those in Table 1. Arrowheads indicate mobility shifts of the PCR products from the genomic DNA from the patients, P1, P2, P3, P4, P5, and P6. (B) Representative sequencing results. Direct sequencing of aberrant bands from P1 identified an A to T transition of the fourth base in intron 4 (indicated by arrows).