There are just a few families informative for one marker and uninformative with another. Many microsatellites markers have been identified linked to APC but none have been found within the gene. These are listed below. YN5.64 and LNS can be multiplexed together, as can LNS, MBC, CB83 and CB26. In the majority of families, it should be possible to obtain informative results for at least one proximal and one distal marker using the microsatellite markers listed above.
Intragenic markers are informative in only a proportion of families.
At least 4 families have been identified which do not show linkage to chromosome 5 markers. The possibility of heterogeneity should therefore be kept in mind when carrying out linkage analysis. In a further proportion of families, affected individuals have often died prior to storage of DNA and again mutation analysis may also be necessary. In some of these cases it may be possible to carry out linkage analysis using DNA extracted from formalin fixed, paraffin embedded material. PCR analysis of fragments up to around 250bp seem to work well, larger fragments less so.