Identification of variable length polyadenosine tract at the dystrophin locus.

We report the characterization of a length polymorphism in the human dystrophin gene, consisting of single-base pair increments in a polyadenosine tract located near the 3' end of exon 68. Using Single Strand Conformation Analysis (SSCA), three length alleles could be identified (10,182 + 13A9/10/11). This class of 1-bp length variant is rare among known intronic gene sequences, and has been described only once in the dystrophin gene. Furthermore, the high polymorphic content (0.56) of this novel marker and its distal localization in the 3' end of the coding sequence make it suitable for diagnostic purposes.