Haploinsufficiency of the gene Quaking (QKI) is associated with the 6q terminal deletion syndrome.

Subtelomeric rearrangements involving chromosome 6q have been reported in a limited number of studies. Although the sizes are very variable, ranging from cytogenetically visible deletions to small submicroscopic deletions, a common recognizable phenotype associated with a 6q deletion could be distilled. The main characteristics are intellectual disabilities, hypotonia, seizures, brain anomalies, and specific dysmorphic features including short neck, broad nose with bulbous tip, large and low-set ears and downturned corners of the mouth. In this article we report on a female patient, carrying a reciprocal balanced translocation t(5;6)(q23.1;q26), presenting with a clinical phenotype highly similar to the common 6q- phenotype. Breakpoint analysis using array painting revealed that the Quaking (QKI) gene that maps in 6q26 is disrupted, suggesting that haploinsufficiency of this gene plays a role in the 6q- clinical phenotype. Copyright 2010 Wiley-Liss, Inc.