Abstract
DiGeorge Syndrome is characterized by a spectrum of congenital malformations. Studies have shown an association between DGS and deletion of chromosome 22 resulting in the loss of 22 pter→q11 and translocation of its distal long arm (22q11→qter) to one of several autosomes (3q, 4q, 10q, 20q). Two cell lines were used for this study. The first, from a balanced translocation carrier, the father of a patient with DGS, has a karyotype of 46, XY, t(10;22)(q25, q11). The der 22 extending from 22pter to q11 is retained. The second cell line, established from a DGS patient, has a karyotype of 45, XY, -4, -22, + der (4), t(4;22)(q35.2;q11.2). This line is monosomic for the region 22pter to q11 and for the region 4q35.2 to qter. “In situ” hybridization with a constant region probe for the immunoglobulin light chain gene cluster (IGLC) reveals strong hybridization to the normal 22 in the q11 region and to the other involved translocation chromosome, 10q+ or 4q+. No hybridization was observed to the der 22 of the balanced carrier. These esults suggest that all of the IGLC constant region from chromosome 22 is translocated to the relevant autosomes involved in these DGS related rearrangements and the breakpoint for each rearrangement is proximal to the c-lambda locus in 22q11. It is possible that the breakpoint for DGS lies within the variable region since v-lambda is proximal to c-lambda in 22q11.
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Cannizzaro, L., Emanuel, B. 805 IN SITU HYBRIDIZATION AND TRANSLOCATION BREAKPOINT (DGS) MAPPING III. DiGEORGE SYNDROME (DGS) WITH PARTIAL MONOSOMY OF CHROMOSOME 22. Pediatr Res 19, 245 (1985). https://doi.org/10.1203/00006450-198504000-00835
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DOI: https://doi.org/10.1203/00006450-198504000-00835