ATRX and Alpha-thalassemia - X-linked intellectual disability syndrome: Furthermore, the identification of ECRs in the ATRX promoter region could provide a starting point for experimental studies to define the minimal promoter of ATRX. While a literature search did not reveal any idiopathic cases of ATR-X syndrome which are could be attributable to mutations in the 5' regulatory regions, an understanding of how ATRX is regulated is an important component of understanding its functions during development and other important biological processes.