Duplication at Xq13.3-q21.1 With Syndromic Intellectual Disability, a Probable Role for the ATRX Gene

作者：Martinez Francisco^*; Rosello Monica; Mayo Sonia; Monfort Sandra; Oltra Silvestre; Orellana Carmen

来源：American Journal of Medical Genetics, Part A, 2014, 164(4): 918-923.

DOI：10.1002/ajmg.a.36371

• XLID
• autism
• hyperactivity
• MECP2
• array CGH

Here we report on two unrelated male patients with syndromic intellectual disability (ID) due to duplication at Xq13.3-q21.1, a region of about 6Mb and 25 genes. Among these, the most outstanding is ATRX, the causative gene of X-linked alpha-thalassemia/mental retardation. ATRX belongs to the growing list of genes implied in chromatin remodeling causing ID. Many these genes, such as MECP2, are dose-sensitive so that not only deletions and point mutations, but also duplications cause ID. Both patients have severe ID, absent expressive speech, early hypotonia, behavior problems (hyperactivity, repetitive self-stimulatory behavior), postnatal growth deficiency, microcephaly, micrognathia, cryptorchidism, low-set, posteriorly angulated ears, and downslanting palpebral fissures. These findings are also usually present among patients with loss-of-function mutations of the ATRX gene. Completely skewed X inactivation was observed in the only informative carrier mother, a constant finding among female carriers of inactivating point mutations of this gene. Participation of other duplicated genes cannot be excluded; nevertheless we propose that the increased dosage of ATRX is the major pathogenic mechanism of this X-linked disorder, a syndrome reminiscent of MECP2 duplication.

• 出版日期2014-4