Complete trisomy 1q with mosaic Y;1 translocation: A recurrent aneuploidy presenting diagnostic dilemmas

Abstract

We present a case of a liveborn male with complete trisomy 1q in mosaic form due to a de novo unbalanced translocation. There are seven previously documented cases of complete trisomy for 1q, which demonstrate that this is a lethal condition. All cases have similar phenotype including weights greater than 50th centile for gestational age, hydrocephalus, microphthalmia, abnormal ears, small mouth or jaw, and abnormal fingers. Single umbilical artery, imperforate anus, and dysplastic kidneys are also seen in more than one patient. Five of the eight translocation cases have identical chromosomal breakpoints involving 1q and Yq. This suggests the possibility of sequence similarities on these two chromosomes as has been documented with several other recurrent chromosomal rearrangements. Further, this case demonstrates the need for postnatal genetics evaluation following prenatal diagnosis. In postnatal testing, the aneuploidy could not be demonstrated in metaphase cells from cultured lymphocytes. More detailed testing prompted by abnormal amniocentesis and neonatal dysmorphology was necessary to confirm the cytogenetic diagnosis. Without the prenatal diagnosis, it is likely that the true cytogenetic aberration would have gone undetected.

Chromosomal anomalies in the etiology of anorectal malformations: A review

“…Scheuerle et al described a case with an imperforate anus without fistula in which mosaicism for an unbalanced Y;1 translocation was found prenatally. Postnatal karyotype was normal, but additional FISH studies were consistent with the mosaic prenatal findings for trisomy 1q [Scheuerle et al, 2005]. Wax et al [2000] described a case of trisomy 1q with imperforate anus, ambiguous genitals and sacrococcygeal teratoma with mosaicism for an unbalanced (1;15) translocation.…”

Prenatal sonographic features of trisomy 1q

“…T risomy 1q is a rare severe chromosomal abnormality with most prenatal diagnoses representing incomplete duplication of the long arm of chromosome 1. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] A characteristic phenotype has been derived from physical and autopsy findings in affected offspring. 5 We describe the prenatal sonographic features associated with 1 case each of complete and partial trisomy1q and summarize the sonographic findings in previously reported complete and partial trisomy 1q.…”

Involvement of interstitial telomeric sequences in two new cases of mosaicism for autosomal structural rearrangements

“…Similarly, Huang et al () explained the mitotic and meiotic instability of a telomere association involving the Y chromosome by the presence of ITSs at the junction of the rearrangements [Huang et al, ]. Of note, five reported cases with pure complete, or almost entire trisomy 1q, involving translocation with the short arm of acrocentric chromosomes, or with Yq12, were in mosaic form [Scheuerle et al, ; Patel et al, ]. These regions, like to human telomeres, consist of DNA repeat sequences, and could have been involved in instability at the fusion point of the derivative chromosomes, as in our cases.…”