A rare balanced parental t (21q; 21q) Robertsonian translocation that results in Down syndrome in all viable pregnancies
Keywords:
Robertsonian, Translocation, Karyotype, Down syndrome, AcrocentricAbstract
We report a case of a rare balanced Robertsonian translocation, t (21q; 21q) in one of the parents that results in adverse pregnancy outcome in 100 % of cases, either first trimester miscarriages or Down syndrome in all viable fetuses. The case highlights the role of optimum genetic evaluation of all cases of reproductive disorders as they can have profound effect over prognosis and further management.
References
Barbara JT. Human cytogenetics: 46 chromosomes, 46 years and counting. Nature Rev Genet. 2002;3:769-78.
Kocarek E, Novatra D. Chromosome analysis in medicine. Cas Lek Cesk. 2002;141:12-5.
Gardner RJM, Sutherland GR. Down syndrome, other full aneuploidies, and polyploidy. In: Gardner RJM, Sutherland GR, eds. Chromosome Abnormalities and Genetic Counselling (Oxford Monograph on medical genetics). 3rd ed. New York : Oxford University Press; 2004.
Chen K, Chmait RH, Vanderbilt D, Wu S, Randolph L. Chimerism in monochorionic dizygotic twins: case study and review. Am J Med Genet Part A. 2013;161A:1817-24.
NHGRI. Chromosome abnormalities, 2006. Available at: http://www.genome.gov/11508982. Accessed 28 January 2015.
Leonard H, Wen X. The epidemiology of mental retardation: challenges and opportunities in the new millennium. Ment Retard Dev Disabil Res Rev. 2002;8:117-34.
Freeman SB, Allen EG, Oxford-Wright CL, Tinker SW, Druschel C, Hobbs CA, et al. The national Down syndrome project: design and implementation 2007. Public Health Rep. 2007;122(1):62-72.
Boue A, Gallano P. A collaborative study of the segregation of inherited chromosome structural rearrangements in 1356 prenatal diagnoses. Prenat Diagn. 1984;4:45-67.
Chen CP, Chern SR, Tsai FJ, Wu PC, Chiang SS, Lee CC, et al. Down syndrome due to unbalanced homologous acrocentric rearrangements and its recurrence in subsequent pregnancies: prenatal diagnosis by amniocentesis. Taiwan J Obstet Gynecol. 2009;48:403-7.
Daniel A, Lam-Po-Tang PR. Structure and inheritance of some heterozygous Robertsonian translocations in man. J Med Gen. 1976;13:381-8.
Keymolen K, Van Berkel K, Vorsselmans A, Staessen C, Liebaers I. Pregnancy outcome in carriers of Robertsonian translocations. Am J Med Genet A. 2011;155:2381.
Scriven PN, Flinter FA, Braude PR, Ogilbie CM. Robertsonian translocations - reproductive risks and indications for preimplantation genetic diagnosis. Hum Reprod. 2001;16(11):2267-73.
Jayalakshamma, Margaret M, Amudha S, Tilak P, Devi R, Rajangam S. Cytogenetic analysis in Down syndrome. Int J Hum Genet. 2010;10(1-3):95-9.
Tolmie JL, MacFayden U. Clinical genetics of common autosomal trisomies. In: Tolmie JL, MacFayden U, eds. Principles and Practice of Medical Genetics. 5th ed. Philadelphia, USA: Churchill Livingstone-Elsevier; 2007: 1015-1026.
Han JY, Choo KHA, Shaffer LG. Molecular cytogenetic characterizations of 17 rob (13q14q) Robertsonian translocations by FISH - narrowing the region containing the breakpoints. Am J Hum Genet. 1994;55:960-7.
Emery AH, Mueller RF. Genetics and the physician. In: Emery AH, Mueller RF, eds. Elements of Medical Genetics. Student’s Note. 8th ed. Edinburgh: Churchill Livingstone; 1992: 279-321.
Furbetta M, Falorni A, Antignani P, Cao A. Sibship. (21q 21q) translocation Down syndrome disorder with maternal transmission. J Med Genet. 1973;10:371-5.
Dallaire L, Fraser FC. Two unusual cases of familial mongolism. Can J Genet Cytol. 1964;6:540-7.
Ercis M, Balci S. Can a parent with balanced Robertsonian translocation t (21q; 21q) have a non-Down’s offspring? Lancet. 1999;353(9154):751.