"Microcytogenetics" and Langer-Giedion syndrome

Cytogenetics of Mendelian mutations associated with cancer proneness

About 5% of Mendelian mutations displaying neoplastic tendencies are associated with chromosomal aberrations. The best established examples are retinoblastoma and del(13)(q14) and aniridia-Wilms' tumor and del(11)(p13). Evidence suggests that both mutations behave as dominant traits in the individual and as recessive traits in the cells. DNA analysis indicates that tumorigenesis arises from homozygosisty for the mutant allele at these loci, as a consequence of mitotic nondisjunction or from a mitotic recombination event. An additional argument for this conclusion is provided by the demonstration of duplication of 11p15 in some patients with the Beckwith-Wiedemann syndrome, which is complicated often by Wilms' tumor and other embryonal tumors. Data obtained with molecular probes have shown that also rhabdomyosarcoma and hepatoblastoma arise by homozygosity for a mutant allele at a locus on 11p, suggesting ontogenic relatedness of these tumor types. Additional examples of Mendelian mutations associated with chromosome deletions and neoplasia include Langer-Giedion syndrome with multiple exostoses and del(8)(q24.1), multiple endocrine neoplasia and del(20)(p12.2). While the presence of specific chromosome changes in subjects with high susceptibility to neoplasia does pinpoint the location of DNA sequences involved in the predisposition to certain types of cancers, selected Mendelian mutations associated with chromosome instability and cancer proneness may elucidate biological principles of cell proliferation and transformation. However, our current knowledge of mechanisms resulting in increased frequency of chromosome breakage and cancer susceptibility in ataxia-teleangiectasia, Fanconi's anemia, Bloom's syndrome, and similar conditions are still very incomplete.

Interstitial deletion of the long arm of chromosome 8 without Langer-Giedion syndrome

A case of interstitial deletion of the long arm of chromosome 8 is reported. A chromosome analysis by a high resolution banding revealed the abnormal karyotype, 46, XY, del (8) (q11.2q13). Although some reports describe an association of 8q deletion with the Langer-Giedion syndrome, this patient did not have the typical features of this syndrome. It was noted that the patient had amino aciduria, EEG and ECG abnormalities together with other pathological findings.

A complex rearrangement, including a deleted 8q, in a case of Langer-Giedion syndrome

A 10-month-old infant with failure to thrive, delayed development, mild dysmorphia, cardiac anomalies, and cryptorchidism was referred for cytogenetic evaluation. Routine GTG-banded analysis revealed a modal number of 46 chromosomes, which contained an obvious complex rearrangement involving chromosomes 1, 8, and 14. Parental chromosomes were normal. Following high resolution techniques, this de novo rearrangement demonstrated an intraband deletion and was designated as [46,XY,t(1;8;14)(1pter----1p13.1::14q12----14pter++ +;1qter----1p13.1::8q24.13----8qter; 14qter----14q12::8p23.3----8q24.11:)]. Although deletions have been implicated as possibly responsible for abnormal phenotypes in patients with de novo "balanced rearrangements", in most cases, they could not be demonstrated. The present case is only the second instance documenting a subtle intraband deletion in association with a complex translocation. Fourteen of the reported 18 patients with an 8q deletion (including this infant) have Langer-Giedion syndrome, suggesting an etiologic relationship. However, the same deletion is not present in all cases.

The tricho-rhino-phalangeal syndrome with exostoses (or Langer-Giedion syndrome): four additional patients without mental retardation and review of the literature

We report on four patients with tricho-rhino-phalangeal syndrome with exostoses (TRPSE) who were not mentally retarded and review 32 previously published cases. These data enable more complete delineation of the phenotype and document the variability of the clinical and radiographic manifestations. Information on the genetics and the association with del(8q) is discussed, as are management and avenues for further investigation. The apparent variability of intelligence in TRPSE patients together with the high incidence of other problems, including significant delay in speech development and hearing loss, make systematic multidisciplinary evaluation and long-term treatment necessary to achieve the best outcome.

Terminal or interstitial deletion in chromosome 8 long arm in Langer-Giedion syndrome (TRP II syndrome)?

Reexamination with high resolution banding of the first ever published case of Langer-Giedion syndrome with 8q deletion as well as chromosome examination of a second case of this syndrome with different high resolution methods, confirmed our previous assumption of a terminal 8q involvement in the causation of TRP II syndrome.

Two cases of the Langer-Giedion syndrome with the same interstitial deletion of the long arm of chromosome 8: 46, XY or XX, del (8) (q23.3q24.13)

Two cases of the Langer-Giedion syndrome (LGS) are reported. Chromosome analysis by high-resolution banding with 850 bands revealed the same abnormal karyotype, 46,XY or XX,del(8)(q23.3q24.13), which was the smallest deletion among those of LGS patients with 8q deletion. The deleted segments found in three patients with LGS analyzed by high-resolution banding have a part of 8q23.3 and 8q24.11 in common.