A Rare De Novo Robertsonian Translocation t(21q; 21q) in an Iranian Child With Down Syndrome: A Case Report
Abstract
Down syndrome or trisomy 21 is the most common genetic disorder with a prevalence of 1 in 700 live-born infants. It is characterized by the intellectual disability of varying range, developmental delay, distinctive facial features and various physical abnormalities. The most frequent clinical features include hypotonia, short stature, short neck, upward slanting eyes, flat nasal bridge, bulging tongue, small ears and a single palmar crease of the hands. Mainly there are three cytogenetic forms of Down syndrome including free trisomy 21, mosaicism and Robertsonian translocation. We describe the case of a 1-year-old Iranian female child who presented to our genetic counseling center with intellectual and physical disabilities. The most common features of Down syndrome were present. The cytogenetic analysis confirmed the diagnosis, with detection of the Robertsonian translocation t(21q; 21q). The patient's parents were found to be both phenotypically and cytogenetically normal, so the identified Robertsonian translocation t(21q; 21q) probably have arisen de novo.
2. Patterson D. Molecular genetic analysis of Down syndrome. Hum Genet. 2009;126(1):195-214.
3. O'nuallain S, Flanagan O, Raffat I, Avalos G, Dineen B. The prevalence of Down syndrome in County Galway. Ir Med J. 2007;100(1):329-31.
4. Roizen NJ, Patterson D. Down's syndrome. Lancet. 2003;361(9365):1281-9.
5. Sherman S, Freeman S, Allen E, Lamb N. Risk factors for nondisjunction of trisomy 21. Cytogenet Genome Res. 2005;111(3-4):273-80.
6. Gardner RM, Sutherland GR, Shaffer LG. Chromosome abnormalities and genetic counseling: OUP USA; 2011.
7. 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(10):2381-5.
8. Kim S-R, Shaffer LG. Robertsonian translocations: mechanisms of formation, aneuploidy, and uniparental disomy and diagnostic considerations. Genet Test. 2002;6(3):163-8.
9. Gardner R, Sutherland G. Down syndrome, other full aneuploidies, and polyploidy. Chromosome abnormalities and genetic counseling: Oxford University Press, New York; 2004. p. 249-56.
10. Zhao W-W, Wu M, Chen F, Jiang S, Su H, Liang J, et al. Robertsonian translocations: an overview of 872 Robertsonian translocations identified in a diagnostic laboratory in China. PloS One. 2015;10(5):e0122647.
11. Kadakol G, Bagoji I, Patil S, Bulagouda R. Cytogenetic Analysis of Down Syndrome. Int J Clin and Biomed Res. 2019:37-40.
12. Gupta NA, Kabra M. Diagnosis and management of Down syndrome. Indian J Pediatr. 2014;81(6):560-7.
13. Hussamy DJ, Herrera CL, Twickler DM, Mcintire DD, Dashe JS. Number of Risk Factors in Down Syndrome Pregnancies. Am J Perinatol. 2019;36(01):079-85.
Files | ||
Issue | Vol 57, No 8 (2019) | |
Section | Case Report(s) | |
DOI | https://doi.org/10.18502/acta.v57i8.2430 | |
Keywords | ||
Down syndrome Intellectual disability Mental retardation Robertsonian translocation De novo t21q: 21q |
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