A functional tetranucleotide (AAAT) polymorphism in an Alu element in the NF1 gene is associated with mental retardation

► Rapid method for genotyping by non-denaturing HPLC a microsatellite (GXAlu). ► Association between carriers of alu4 (microsatellite) and mental retardation. ► Increased expression of a reporter gene with alu4 and alu5 (microsatellite).