Balanced reciprocal whole arm translocation t(3;9): analysis by fluorescence in situ hybridisation.

Abstract

A patient with Turner phenotype was found to carry two de novo chromosome aberrations: a 45,X line and a whole arm reciprocal translocation t(3;9). Fluorescence in situ hybridisation on metaphase cells using a satellite DNA for chromosome 3 and P satellite and 'classical' satellite DNA for chromosome 9 showed that the centromeric region of chromosome 3 was retained in the 3q9q translocation derivative, as was the secondary constriction heterochromatin of chromosome 9. No signals were observed in the 3p9p derivative with the three probes. This suggests that the breakpoints were on 3pll and 9qll. The karyotype was 45,X,t(3;9)(3qter-+3pl l::9ql 1 -9qter; 9pter-+9q1l::3pl1 -3pter). (J Med Genet 1994;31:74-75) Constitutional whole arm reciprocal translocations are rare. To our knowledge only a few cases have been reported. "Most of them were found in phenotypically normal subjects and some in patients with reproductive failure.46 In contrast, whole arm translocations are not uncommon in cancer cells where fluorescence in situ hybridisation (FISH) has been used to obtain more information on the breakpoints and involvement of centromeric DNA sequences in the chromosome rearrangements.78We report a patient with 45,X Turner syndrome and a whole arm reciprocal translocation t(3;9) where in situ hybridisation studies, combined with cytogenetic analysis, allowed us to define the breakpoints and the origin of centromeres in the derivative chromosomes. Case report A 19 year old female was referred because of short stature and absence of secondary sexual characteristics. She was the eighth child of healthy, unrelated parents. At birth, oedema of the hands and feet was noted and at 10 years of age the parents were concerned about her short stature. Physical examination showed a height of 1 36 m, multiple naevi, a short neck, broad chest with widely spaced nipples, cubitus valgus, and shortening of the fourth metacarpal and metatarsal bones. Intelligence was average. Cytogenetic studies of peripheral blood with G banding showed two chromosome aberrations: 45,X and a whole arm reciprocal translocation between chromosomes 3 and 9 (fig 1). The proposed karyotype was 45,X,t(3;9)(3p9p;3q9q). C banding showed that 9qh heterochromatic region was retained on the der(3q9q); however, the precise breakpoints at the centromeres or on p or q could not be defined.Chromosome studies of both parents were normal.

Prenatal diagnosis and characterization of an unbalanced whole arm translocation resulting in monosomy for 18p

“…For example, in the balanced der(1;19) described by Gravholt et al [22] the chromosome 1 α‐satellite region was split by the translocation, whereas the chromosome 19 α‐satellite region was retained entirely on the der[19]. Peri‐centromeric, non‐α‐satellite breakpoints were reported in two other balanced whole arm translocations [4,25]. Two additional whole arm translocations were examined with probes for only one of the centromeres involved and also showed an α‐satellite breakpoint [2,26].…”

NOTCH2 Is Neither Rearranged nor Mutated in t(1;19) Positive Oligodendrogliomas

“…This suggests that the specific architecture of these segments might be more prone to chromosomal rearrangements, thus mediating chromosome breakage and generating the aforementioned 1p/19q translocation. Alphoid repeats have already been documented in some derivatives of the recurrent translocations suggesting genomic instability as a cause of arm-to-arm translocations in several types of tumors [26] – [28] . We cannot exclude other mechanisms that may be responsible for the profiles revealed by the array-CGH analysis of these 1p/19q co-deleted cases.…”

Balanced nonacrocentric whole‐arm reciprocal translocations: A de novo case and literature review

“…Given the limited number of balanced whole-arm reciprocal translocations reported, it is surprising that 2 appear to be identical, perhaps suggesting a nonrandom propensity for chromosome breakage and reunion of these centromeres. a-and p-satellite DNA sequences have been used to determine the centromere of the chromosome of origin and to identify the breakpoints in 3 reports [Blanco et al, 1994;Cantu et al, 1992;Tharapel et al, 19911. Unfortunately, the available DNA probes were not able to distinguish the centromeres of chromosomes 1 and 5 for our case.…”