Figure 1. Screening of c.1999A>C mutation by an allele-specific polymerase chain reaction. Polymerase chain reaction (PCR) was performed in presence of two pairs of primers, one for amplification of a 456 bp fragment in FBN1 and the other for amplification of a 259 bp fragment in LTBP2. The former served as control for efficacy of the PCR reaction. The 3′ terminus of the forward primer for the LTBP2 fragment was designed to amplify only the mutated allele (c.1999C) and not the wild-type allele. M, size markers; patient with PEX, template was from patient with PEX carrying a mutation; template in all other lanes is from control individuals. The arrow on the left shows the migration position of the LTBP2 product, and the arrow on the right shows migration position of FBN1 product. Comparable results were obtained in all 100 controls screened.