6.1. Detection of FH-Helsinki by polymerase chain reaction

The clinical diagnosis of FH is based on an elevated LDL cholesterol level and tendon xanthomata and supported by the existence of CAD in a first-degree relative. In accordance with the previously published data (Thompson et al. 1989), 83% of our FH patients had tendon xanthomata. However, the diagnosis of FH can be difficult, especially in adolescents who have not yet developed tendon xanthomata. Since the subjects would benefit from therapeutic interventions, a simple and rapid diagnostic test is needed.

The PCR method is most applicable in homogenous populations with a founder gene mutation. The FH-Helsinki mutation is a founder mutation in Finland and responsible for almost half of the FH cases in Finland (Aalto-Setälä et al. 1988a, Aalto-Setälä et al. 1989a). Another PCR method with two pairs of oligonucleotides has been applied to the diagnosis of FH-Helsinki, whereas the method described here involves only one pair of oligonucleotides. The results show that the prevalence of the FH-Helsinki mutation is even higher in Northern than in Southern Finland, 62% and 33%, respectively, supporting the use of the test in this area.