(a) Comparison of the TaqI restriction fragment patterns of long RT-PCR products containing FBN1 exons 29–52. Sample C is amplified from a normal control, PI represents patient 1 (FB774) and P2 patient 2 (and FB890). Lane 1 is a 100 bp ladder. Arrows point to the abnormal fragments in the patient lanes. (b) Direct sequencing analysis of the DNA isolated from the altered restriction fragments reveals deletion of exons 42–43 in patient 1 (top) and of exons 44–46 in patient 2 (bottom).