Vacuoliting Megalencephalic Leukoencephalopathy

To the Editor:

In a report in the February 2000 issue of the Journal, Topçu et al. (2000) reported on the mapping of vacuoliting megalencephalic leukoencephalopathy with subcortical cysts to chromosome 22q, in a 3-cM interval between the markers D22S1161 and n66c4. The centromeric boundary was defined by a recombination event with the marker D22S1161. However, how n66c4 was determined as the telomeric boundary is not clear. n66c4 reaches its maximal LOD score at θ=.00. The highest multipoint LOD score was also reached with that marker, and the haplotypes shown in figure 2 of the report do not reveal any recombination events with this marker, either in the patients or in the unaffected sibs. The interval containing the gene should therefore be defined as being between D22S1161 and the telomere.