Inversion‐duplication of bands q13→q21 of human chromosome 9

Publisher Website
Google Scholar
Abstract
Structural abnormalities involving heterochromatic regions of the human genome are difficult to characterize because these segments are G‐band negative by GTG technique, a routinely used procedure in clinical cytogenetic laboratories. Chromosome abnormalities of such cases have gone undetected or were incorrectly characterized because these regions are so‐called heteromorphisms or variants. Consequently, much anxiety has been aroused by the confusion between a chromosome abnormality and a normal heteromorphic variant. We report the first documented case with a so‐called highly unusual h region of chromosome 9 which is not a variation but a structural rearrangement involving a paracentric inversion and a duplication. The major clinical features were psychomotor retardation, microcephaly, narrow palpebral fissures, renal and genital anomalies, vertebral anomalies, protruding tongue, and learning and behavioral problems. A concise review of variable duplicated segments of 9q is also provided.