Fig. 4

Electrophoretic analysis of RT-PCR reveals a splicing defect in three cases. (A) IVS2-2 a→c; retention of a 34-bp fragment of the 3′-end of intron 2. Lane 1 DNA molecular weight marker VI (Boehringer Mannheim, Germany). Lane 2 A 413 bp normal RT-PCR fragment including exons 2 to 5 and a 447 bp mutant fragment. Lane 3 A 503 bp normal RT-PCR fragment including exons 1 to 5 and a 537 bp mutant fragment. (B) 338 G→C; deletion of exon 4. Lane 1 A 359 bp normal RT-PCR fragment including exons 3 to 5 and a 243 bp mutant fragment. Lane 2. The RT-PCR was reamplified after BsaI digestion abolishing the normal transcript. Lane 3 DNA molecular weight marker VI. (C) 470 A→C; deletion of exon 5 and a 19 bp retention of the 3′-end of intron 5 result in a total deletion of 114 bp in the mutant transcript. Lane 1 A 250 bp normal RT-PCR fragment including exons 4 to 6 and a 136 bp mutant fragment. Lane 2 DNA molecular weight marker VI.