Journal of Postgraduate Medicine
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Year : 2014  |  Volume : 60  |  Issue : 4  |  Page : 413  

Prenatal diagnosis of partial trisomy 21 associated with maternal balanced translocation 46,XX, der(21)t(21;22) with pericentric inversion of chromosome 9

B Kar 
 Center for Genetic Studies and Research, The Madras Medical Mission, Chennai, Tamilnadu, India

Correspondence Address:
Dr. B Kar
Center for Genetic Studies and Research, The Madras Medical Mission, Chennai, Tamilnadu
India




How to cite this article:
Kar B. Prenatal diagnosis of partial trisomy 21 associated with maternal balanced translocation 46,XX, der(21)t(21;22) with pericentric inversion of chromosome 9.J Postgrad Med 2014;60:413-413


How to cite this URL:
Kar B. Prenatal diagnosis of partial trisomy 21 associated with maternal balanced translocation 46,XX, der(21)t(21;22) with pericentric inversion of chromosome 9. J Postgrad Med [serial online] 2014 [cited 2022 Oct 6 ];60:413-413
Available from: https://www.jpgmonline.com/text.asp?2014/60/4/413/143978


Full Text

Sir,

In the case report published in 2003 "Prenatal Diagnosis of Partial Trisomy 21 Associated With Maternal Balanced Translocation 46xx Der 21 t(21q;22q) With Pericentric Inversion of Chromosome 9", [1] the karyotype mentioned appears to be incorrect. It should be interpreted as 45,XX,inv(9)(p11q11),der(21;22)(q10;q10) as per the International System for Human Cytogenetic Nomenclature (ISCN), 2005 guidelines.

While the nomenclature is two years later than the paper itself, the karyotype pictures of both the foetus and mother are identical (a copy of the same image) except the G group i.e., chromosomes 21 and 22 where some changes are seen. It is not clear how the morphology and anatomy of chromosomes could be the same in the case of the fetus and the mother. One can easily note that in the homologous pair of chromosome 21, one chromosome 21 which is pasted on the left side is taken from other metaphase and is pasted in the picture of foetal karyotype and rest are the same as shown in the mother karyotype except the manipulation like pasting or pairing the derivative 21 i.e., der(21;22) with normal chromosome 22 instead of pairing with chromosome 21. From the above, I wonder whether the authors have performed the amniocentesis at 17 th week of gestation. Even if the amniocentesis had been performed, the authors may not have got a successful culture to report the cytogenetic findings. Both foetal and maternal karyotypes mentioned in page no. 155 are incorrect and should be interpreted as 46,XX,der(21;22)(q10;q10),+21 and 45,XX,inv(9)(p11q11),der(21;22)(q10;q10) respectively. Pericentric inversion of chromosome 9 should be read as inv(9) instead of PIC 9.

References

1Parmar RC, Sira P. Prenatal diagnosis of partial trisomy 21 associated with maternal balanced translocation 46xx der 21 t(21q;22q) with pericentric inversion of chromosome 9. J Postgrad Med 2003 49:154-6.

 
Thursday, October 6, 2022
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