SPOKANE, Wash.--(BUSINESS WIRE)--Microscopic deletions of chromosome 3q29 have been described recently in individuals with mental retardation and highly variable clinical features. All individuals reported to date have the same-sized deletion. Because this region of chromosome 3 is thought to be caused by recombination between flanking segments of highly repetitive DNA sequences, duplications of 3q29 should occur with the same frequency as deletions. However, with the exception of one three-generation family, no individuals with microduplications of 3q29 have been reported. Researchers at Signature Genomic Laboratories recently characterized 19 individuals with 3q29 microduplications and suggest that duplication alone may not account for the clinical features in those individuals.
