Publication:
Free Text: Spectral Karyotyping for identification of constitutional chromosomal abnormalities at a national reference laboratory.


abstract

ABSTRACT: Spectral Karyotyping is a diagnostic tool that allows visualization of chromosomes in different colors using the FISH technology and a spectral imaging system. To assess the value of spectral karyotyping analysis for identifying constitutional supernumerary marker chromosomes or derivative chromosomes at a national reference laboratory, we reviewed the results of 179 consecutive clinical samples (31 prenatal and 148 postnatal) submitted for spectral karyotyping. Over 90% of the cases were requested to identify either small supernumerary marker chromosomes (sSMCs) or chromosomal exchange material detected by G-banded chromosome analysis. We also reviewed clinical indications of those cases with marker chromosomes in which chromosomal origin was identified by spectral karyotyping. Our results showed that spectral karyotyping identified the chromosomal origin of marker chromosomes or the source of derivative chromosomal material in 158 (88%) of the 179 clinical cases; the identification rate was slightly higher for postnatal (89%) compared to prenatal (84%) cases. Cases in which the origin could not be identified had either a small marker chromosome present at a very low level of mosaicism (< 10%), or contained very little euchromatic material. Supplemental FISH analysis confirmed the spectral karyotyping results in all 158 cases. Clinical indications for prenatal cases were mainly for marker identification after amniocentesis. For postnatal cases, the primary indications were developmental delay and multiple congenital anomalies (MCA). The most frequently encountered markers were of chromosome 15 origin for satellited chromosomes, and chromosomes 2 and 16 for non-satellited chromosomes. We were able to obtain pertinent clinical information for 47% (41/88) of cases with an identified abnormal chromosome. We conclude that spectral karyotyping is sufficiently reliable for use and provides a valuable diagnostic tool for establishing the origin of supernumerary marker chromosomes or derivative chromosomal material that cannot be identified with standard cytogenetic techniques.

Related Articles
The identification of small supernumerary marker chromosomes; the experiences of 15,792 fetal karyotyping from Turkey.
Eur J Med Genet. 2006
The identification of small supernumerary marker chromosomes; the experiences of 15,792 fetal karyotyping from Turkey.
Karaman B, Aytan M, Yilmaz K, Toksoy G, Onal EP, Ghanbari A, Engur A, Kayserili H, Yuksel-Apak M, Basaran S. Eur J Med Genet. 2006 May-Jun; 49(3):207-14. Epub 2005 Jul 12.
Characterization of 23 small supernumerary marker chromosomes detected at pre-natal diagnosis: The value of fluorescence in situ hybridization.
Mol Med Report. 2010
Characterization of 23 small supernumerary marker chromosomes detected at pre-natal diagnosis: The value of fluorescence in situ hybridization.
Manolakos E, Kefalas K, Neroutsou R, Lagou M, Kosyakova N, Ewers E, Ziegler M, Weise A, Tsoplou P, Rapti SM, et al. Mol Med Report. 2010 Nov-Dec; 3(6):1015-22. Epub 2010 Sep 10.
Identification of de novo chromosomal markers and derivatives by spectral karyotyping.
Hum Genet. 1998
Identification of de novo chromosomal markers and derivatives by spectral karyotyping.
Haddad BR, Schröck E, Meck J, Cowan J, Young H, Ferguson-Smith MA, du Manoir S, Ried T. Hum Genet. 1998 Nov; 103(5):619-25.
Review SKY assessment of two karyotypes with 0-6 supernumerary marker/ring chromosomes and review of previously reported cases with two or more markers.
Am J Med Genet A. 2003
Review SKY assessment of two karyotypes with 0-6 supernumerary marker/ring chromosomes and review of previously reported cases with two or more markers.
Reddy KS, Wang S, Groh S, Gonatos J. Am J Med Genet A. 2003 Apr 15; 118A(2):156-71.
Review Characterization of a small supernumerary marker chromosome as r(8) at prenatal diagnosis by MFISH.
Prenat Diagn. 2005
Review Characterization of a small supernumerary marker chromosome as r(8) at prenatal diagnosis by MFISH.
Gole LA, Biswas A. Prenat Diagn. 2005 Jan; 25(1):73-8.