Abstract
Cryptic telomere deletions have been proposed to be a significant cause of idiopathic mental retardation. We present two unrelated subjects, with normal G banding analysis, in whom 22q telomere deletions were serendipitously detected at two different institutions using fluorescence in situ hybridisation (FISH). Both probands presented with several of the previously described features associated with 22q deletions, including hypotonia, developmental delay, and absence of speech. Our two cases increase the total number of reported 22q telomere deletions to 19, the majority of which were identified by cytogenetic banding analysis. With the limited sensitivity of routine cytogenetic studies (approximately 2-5 Mb), these two new cases suggest that the actual prevalence of 22q telomere deletions may be higher than currently documented. Of additional interest is the phenotypic overlap with Angelman syndrome (AS) as it raises the possibility of a 22q deletion in patients in whom AS has been ruled out. The use of telomeric probes as diagnostic reagents would be useful in determining an accurate prevalence of chromosome 22q deletions and could result in a significantly higher detection rate of subtelomeric rearrangements.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chong S. S., Pack S. D., Roschke A. V., Tanigami A., Carrozzo R., Smith A. C., Dobyns W. B., Ledbetter D. H. A revision of the lissencephaly and Miller-Dieker syndrome critical regions in chromosome 17p13.3. Hum Mol Genet. 1997 Feb;6(2):147–155. doi: 10.1093/hmg/6.2.147. [DOI] [PubMed] [Google Scholar]
- Doheny K. F., McDermid H. E., Harum K., Thomas G. H., Raymond G. V. Cryptic terminal rearrangement of chromosome 22q13.32 detected by FISH in two unrelated patients. J Med Genet. 1997 Aug;34(8):640–644. doi: 10.1136/jmg.34.8.640. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Flint J., Wilkie A. O., Buckle V. J., Winter R. M., Holland A. J., McDermid H. E. The detection of subtelomeric chromosomal rearrangements in idiopathic mental retardation. Nat Genet. 1995 Feb;9(2):132–140. doi: 10.1038/ng0295-132. [DOI] [PubMed] [Google Scholar]
- Herman G. E., Greenberg F., Ledbetter D. H. Multiple congenital anomaly/mental retardation (MCA/MR) syndrome with Goldenhar complex due to a terminal del(22q). Am J Med Genet. 1988 Apr;29(4):909–915. doi: 10.1002/ajmg.1320290423. [DOI] [PubMed] [Google Scholar]
- Narahara K., Takahashi Y., Murakami M., Tsuji K., Yokoyama Y., Murakami R., Ninomiya S., Seino Y. Terminal 22q deletion associated with a partial deficiency of arylsulphatase A. J Med Genet. 1992 Jun;29(6):432–433. doi: 10.1136/jmg.29.6.432. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nesslinger N. J., Gorski J. L., Kurczynski T. W., Shapira S. K., Siegel-Bartelt J., Dumanski J. P., Cullen R. F., Jr, French B. N., McDermid H. E. Clinical, cytogenetic, and molecular characterization of seven patients with deletions of chromosome 22q13.3. Am J Hum Genet. 1994 Mar;54(3):464–472. [PMC free article] [PubMed] [Google Scholar]
- Ning Y., Rosenberg M., Biesecker L. G., Ledbetter D. H. Isolation of the human chromosome 22q telomere and its application to detection of cryptic chromosomal abnormalities. Hum Genet. 1996 Jun;97(6):765–769. doi: 10.1007/BF02346187. [DOI] [PubMed] [Google Scholar]
- Phelan M. C., Thomas G. R., Saul R. A., Rogers R. C., Taylor H. A., Wenger D. A., McDermid H. E. Cytogenetic, biochemical, and molecular analyses of a 22q13 deletion. Am J Med Genet. 1992 Jul 15;43(5):872–876. doi: 10.1002/ajmg.1320430524. [DOI] [PubMed] [Google Scholar]
- Romain D. R., Goldsmith J., Cairney H., Columbano-Green L. M., Smythe R. H., Parfitt R. G. Partial monosomy for chromosome 22 in a patient with del(22)(pter----q13.1::q13.33----qter). J Med Genet. 1990 Sep;27(9):588–589. doi: 10.1136/jmg.27.9.588. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Watt J. L., Olson I. A., Johnston A. W., Ross H. S., Couzin D. A., Stephen G. S. A familial pericentric inversion of chromosome 22 with a recombinant subject illustrating a 'pure' partial monosomy syndrome. J Med Genet. 1985 Aug;22(4):283–287. doi: 10.1136/jmg.22.4.283. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wong A. C., Ning Y., Flint J., Clark K., Dumanski J. P., Ledbetter D. H., McDermid H. E. Molecular characterization of a 130-kb terminal microdeletion at 22q in a child with mild mental retardation. Am J Hum Genet. 1997 Jan;60(1):113–120. [PMC free article] [PubMed] [Google Scholar]
- Yong Y. P., Knight L. A., Yong M. H., Lam S., Ho L. Y. Partial monosomy for chromosome 22 in a girl with mental retardation. Singapore Med J. 1997 Feb;38(2):85–86. [PubMed] [Google Scholar]