Lack of association of the (AAAT)(6) allele of the GXAlu tetranucleotide repeat in intron 27b of the NF1 gene with autism

A novel allele of the GXAlu tetranucleotide repeat in intron 27b of the neu rofibromatosis 1 (NF1) gene has recently been reported to be present in 4.7 % of autistic patients but not in controls. We have found the novel GXAlu a llele absent in 204 patients from the South Carolina Autism Project and 200 controls. The autism population studied includes a significant number of p atients with hypotonia, stereotyped behaviors, or postural, gait, and motor abnormalities similar to those seen in the patients previously reported to possess the novel GXAlu allele, This suggests that the novel (AAAT)(6) GXA lu allele is not associated with autism. (C) 2001 Wiley-Liss. Inc.