[2] Males with this condition tend to be moderately intellectually disabled and have physical characteristics including coarse facial features, microcephaly (small head size), hypertelorism (widely spaced eyes), a depressed nasal bridge, a tented upper lip and an everted lower lip.

[4] Females with this mutated gene have no specific signs or features, but if they do, they may demonstrate skewed X chromosome inactivation.

"The role of ATRX as a regulator of heterochromatin dynamics raises the possibility that mutations in ATRX may lead to downstream transcriptional effects across the complex of genes or repetitive regions involved in the global context of the disorder, in addition to explaining phenotypical differences in these patients.

[5] It's important to recognize that having a mutation in the ATRX gene does not necessarily guarantee that the patient has ATR-X syndrome.

[5] However, it is common within ATR-X patients to have global hypermethylation of usually unmethylated regions, like CpG islands and promoters.

ATR-16 syndrome patients have a 1-2Mb deletion on the top of the chromosome 16 p-arm and are associated with a Mendelian inheritance of a-thalassemia.