Direct detection of missense mutation Leu₁₂₈→ Pro in plasminogen exon 5 of patient no. 5 by RFLP analysis. Amplified PCR products of plasminogen exon 5 were digested withMsp I, electrophoresed in a 2% agarose gel, and visualized by ethidium bromide staining. The (uncut) wild-type PCR fragment has a size of 221 bp; the mutant Msp I-digested PCR fragment has a size of 144 bp. −, no Msp I added to PCR product; +,Msp I added to PCR product. Lane M, 100-bp ladder; lane 1, healthy control; lane 2, father of patient no. 5; lane 3, mother of patient no. 5; lane 4, patient no. 5. The shorter (mutant type) allele is found after Msp I-digestion in patient no. 5 and his mother (lanes 3+ and 4+, heterozygous), but not in his father (lane 2+) and not in a healthy control (lane 1+).