A t(7;12) balanced translocation with breakpoints overlapping those of the Williams-Beuren and 12q14 microdeletion syndromes.
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.
Gimelli
Stefania
S
Biologia Generale e Genetica Medica, Universita' di Pavia and IRCCS C. Mondino, Pavia, Italy. stefania.gimelli@gmail.com
Chrast
Jacqueline
J
Baban
Anwar
A
Henrichsen
Charlotte N
CN
Lerone
Margherita
M
Zuffardi
Orsetta
O
Gimelli
Giorgio
G
Reymond
Alexandre
A
D002460:Cell Line; D002871:Chromosome Banding; D019457:Chromosome Breakage; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics*; D002897:Chromosomes, Human, Pair 7 / Q000235:genetics*; D055028:Comparative Genomic Hybridization; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007621:Karyotyping; D011247:Pregnancy; D014178:Translocation, Genetic; D018980:Williams Syndrome / Q000235:genetics*