Chromosome 12q12 deletion – confirmation of an ARID2 gene defect

Van Paemel et al. “Confirmation of an ARID2 defect in SWI/SNF-related intellectual disability”. American Journal of Medical Genetics, 2017, v. 173, 3104-3108.

The ARID (AT rich interaction domain) group of genes belongs to a family known as the SWItch/Sucrose NonFermentable (SWI/SNF) complex involved in gene regulation and development. The ARID2 located at 12q12 is one of the genes in this group.

The authors report on a girl with a small deletion in 12q12, affecting only the ARID2 gene. This girl had intellectual disability (ID), non-specific dysmorphic features, brachymesophalangia (shortening of the middle phalanges of the fingers) and hypoplastic nails on the 5^th fingers. Similar manifestations are characteristic also for Coffin-Siris syndrome (CSS), caused by mutations in ARID1A or ARID1B genes, and Nicolaides-Baraitser syndrome (NBS), caused by mutation of another gene of the SWI/SNF complex.

This article raises the issue of whether CSS, NBS, and ARID2-related intellectual disability should be considered three separate disorders, or regarded as the same disorder – a collection of symptoms known as “SWI/SNF-related ID syndromes”. Since they have similar symptoms and involve the same proteins, evidence suggests that these disorders are related to some degree. However, more reported cases of these diseases need to be evaluated before any conclusions can be drawn.