Am J Med Genet A.; Group Reymond

Am J Med Genet A. 2010 May;152A(5):1285-94.

A t(7;12) balanced translocation with breakpoints overlapping those of the Williams-Beuren and 12q14 microdeletion syndromes.

Gimelli SChrast JBaban AHenrichsen CNLerone MZuffardi OGimelli GReymond A.

Biologia Generale e Genetica Medica, Universita’ di Pavia and IRCCS C. Mondino, Pavia, Italy.


The molecular characterization of balanced chromosomal rearrangements have always been of advantage in identifying disease-causing genes. Here, we describe the breakpoint mapping of a de novo balanced translocation t(7;12)(q11.22;q14.2) in a patient presenting with a failure to thrive associated with moderate mental retardation, facial anomalies, and chronic constipation. The localization of the breakpoints and the co-occurrence of Williams-Beuren syndrome and 12q14 microdeletion syndrome phenotypes suggested that the expression of some of the dosage-sensitive genes of these two segmental aneuploidies were modified in cells of the proposita. However, we were unable to identify chromosomes 7 and/or 12-mapping genes that showed disturbed expression in the lymphoblastoids of the proposita. This case showed that position-effect might operate in some tissues, but not in others. It also illustrates the overlap of phenotypes presented by patients with the recently described 12q14 structural rearrangements.

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