The 6p subtelomere deletion syndrome

AbstractSubmicroscopic deletion of the 6p25 subtelomere has recently been recognized as a clinically identifiable syndrome. To date, more than 30 cases have been described with variable cytogenetically visible 6p deletions. Terminal 6p deletions result in a clinically distinguishable phenotype. The focus of this review is the phenotype associated with isolated terminal deletions of 6p25, and specifically isolated submiscroscopic subtelomere deletions. A distinct phenotype has emerged consisting of developmental delay/mental retardation, language impairment, hearing loss, and ophthalmologic, cardiac, and craniofacial abnormalities. These features demonstrate considerable clinical overlap with the Ritscher‐Schinzel (or cranio‐cerebello‐cardiac (3C)) syndrome (OMIM #220210). Isolated submiscroscopic 6p25 subtelomere terminal deletion has been reported in 11 individuals, two of whom are siblings. Cytogentic and molecular mapping of the 6p25 deletion boundary has been reported in 8 of these 10 unrelated individuals with isolated submiscroscopic subtelomere deletion. This analysis has revealed substantial phenotypic overlap between individuals with submicroscopic terminal 6p deletions an