Unusual mosaic karyotype resulting from adjacent 1 segregation of t(11;22): Importance of performing skin fibroblast karyotype in patients with unexplained multiple congenital anomalies

Abstract

We report a patient with a mosaic karyotype resulting from an adjacent 1 segregation of the familial autosomal translocation (11;22). The karyotype seen in fibroblast is 46,XY,der(22)t(11;22)(q23.3;q11.2)/46,XY. No evidence of the abnormal cell line was seen in the cultures obtained from the lymphocytes. The clinical phenotype of the patient does not fit a particular pattern of partial monosomy 22 or partial trisomy 11. There are some features that have been previously reported in patients with trisomy 11q23 --> qter. The mosaic karyotype in our patient could be a result of a series of postzygotic mitotic events of a zygote carrying the der(22) chromosome. These mechanisms involve events that are well documented for several chromosomes. This case underscores the necessity of performing exhaustive cytogenetic analysis in patients with an abnormal phenotype with a family history of a chromosome rearrangement in fibroblast cells if lymphocyte analysis is normal.

Using Array-Based Comparative Genomic Hybridization to Diagnose Pallister-Killian Syndrome

“…Phytohemagglutinin is often used in chromosomal analysis to stimulate T lymphocytes to divide. If abnormal cells are less competitive than are normal cells in stem cell populations, then they may be underrepresented in stimulated cultures [89]. Therefore, cells with isochromosome 12p are likely to be selected against during cell culture [10].…”

A unique case of der(11)t(11;22),-22 arising from 3:1 segregation of a maternal t(11;22) in a family with co-segregation of the translocation and breast cancer

“…The single example with a 46,XX,der(22) karyotype, with monosomy for 22q and trisomy for 11q, was found in an early embryonic death resulting in an empty sac (Soler et al, 1993). The other cases produced viable offspring due to subsequent events that rescued the monosomy 22: in one case through a maternal MI nondisjunction of 22 (Dawson et al, 1996), and, in others, most probably by postzygotic nondisjunction involving the der (22) chromosome (Kulharya et al, 2002). Five cases with karyotype 47,t(11;22),+der(22) and phenotype similar to the usual der(22) have been reported (Lockwood et al, 1989;Abeliovich and Carmi, 1990;Lurie and Podelschuk, 1992;Simi et al, 1992;Petkovic et al,1996).…”

Chromosomal mosaicism in familial reciprocal translocation carriers: Necessity of karyotyping different tissues

“…Considering the small excess of MR/CM in children who carry familial reciprocal translocations [Fryns et al, 1991] the report by Kulharya et al [2002] encourages us to stress again the importance of performing cytogenetic analyses from different tissue types in this group of patients. The described mosaicism might be the exception but it may not be a rarity.…”

“…Recently in this journal an article was published by Kulharya et al [2002] that describes an unusual mosaic karyotype resulting from an adjacent 1 segregation of the familial autosomal translocation (11;22). Cytogenetic analyses from lymphocytes of a patient with multiple congenital anomalies showed a normal male karyotype, whereas in fibroblasts a mosaic karyotype 46,XY,der(22)t(11;22)(q23.3;q11.2)/46,XY had been detected.…”