A de novo complex t(7;13;8) translocation with a deletion in the TRPS gene region

Abstract

Molecular cytogenetic analyses have resolved the pathogenetic aberration of an 8-year-old girl with tricho-rhino-phalangeal syndrome type I (TRPS I), normal intelligence, and a karyotype originally described as 46,XX,t(8;13)(q24;q21). R- and Q-banding and high resolution R-banding analyses have also disclosed a seemingly mosaic abnormality of the distal short arm of chromosome 7 but have not fully characterized this abnormality. Combined primed in situ labelling and chromosome painting, and three-colour chromosome painting have revealed a complex, apparently balanced translocation t(7;13;8). Fluorescence in situ hybridization with yeast artificial chromosome and cosmid clones from 8q24.1 has shown an interstitial deletion of at least 3 Mb covering most of the TRPS I critical region.

Deletion in the ABL gene resulting from a meiotic recombination of a maternal (3;22;9)(q22;q12;q34.1) translocation

“…As described in several reports, conventional cytogenetic techniques have limitations in the analysis of complex rearrangements. [10][11][12] In our case, the use of whole chromosome painting probes allowed us to identify the derivative chromosome 9 and specific locus probes near breakpoints showed the presence of a cryptic deletion of the chromosomal band 9q34.1. Wirth et al 9 estimated that a significant proportion of cytogenetically balanced translocations (>10%) have submicroscopic deletions of several megabases that account for the associated clinical phenotype.…”

Das Trichorhinophalangealsyndrom

“…Demgegenüber wird der Typ II des TRPS durch eine ausgedehntere Deletion benachbarter Chromosomenanteile hervorgerufen ("contiguous gene syndrome"; [19]). Da multiple Exostosen auch außerhalb des TRPS auftreten, wird für die Kodierung ein vom TRPS unabhängiger Genlokus auf Chromosom 8 angenommen, genannt EXT1 [3], der distal der Bande 8q24.11 liegt [14]. Yamamoto et al [37] vermuten dieses Gen auf der distalen Hälfte von 8q24.13.…”

Genes and chromosomal breakpoints in the Langer-Giedion syndrome region on human chromosome 8

“…The distal deletion breakpoints of patients JL1386 and CR5568 map to YAC 340B11 Brandt et al 1997), which also spans the proximal border of the deletion SRO of TRPS II patients ( Fig. The breakpoints of patients EA, t(8;9), NS, inv(8)(qq), and CR5568, t(7;8;13), have been described by Hou et al (1995), Sasaki et al (1997), and Brandt et al (1997), respectively. Patient NS has TRPS I and a paracentric inversion associated clones (p17-EST-contig) outside the TRPS II del SRO has been identified by database searches with the evolutionarily conserved sequence p17 (D8S43).…”

“…All patients with TRPS II have large deletions, which define a shortest region of deletion overlap (deletion SRO) of approximately 2 Mb in 8q24.1. The distal deletion breakpoints of patients JL1386 and CR5568 map to YAC 340B11 Brandt et al 1997), which also spans the proximal border of the deletion SRO of TRPS II patients ( Fig. Two of them, the translocation breakpoints in patients KS2166 and EA (Hou et al 1995), defined, so far, the proximal and distal borders of the minimal TRPS1 gene region, which overlaps with the TRPS II deletion SRO (Fig.…”