Complex chromosome rearrangements and congenital anomalies

Abstract

Congenital complex chromosome rearrangements (CCR) compatible with life are rare in man. Thus patients with CCR usually present considerable diagnostic difficulties both clinically and cytogenetically. We studied a 12-year-old mentally retarded male with minor congenital anomalies as described below and his first-degree relatives. The propositus had an unbalanced karyotype with eight break points and seven derivative chromosomes; two deletions, del(6) (q25----qter) and del(14) (q31----qter), and four translocations, t(2;11), t(5;15), t(6;11), t(6;20) were present. Parental chromosomes were normal; however, the mother had a few metaphases with abnormal chromosomes suggestive of chromosome instability. These findings and a review of reported patients with CCR are presented with regard to speculations about etiology, pathogenesis, phenotypic expression, and prognosis. Physicians should be aware of CCR and broader indications for cytogenetic studies appear warranted in view of these data.

Complex chromosome rearrangements: Report of three patients

“…The importance of extrinsic factors has repeatedly been stressed, such as viral infection and exposure to radiation or chemicals in the parents, particularly the mothers, of the CCR carriers (Kousseff et al, 1987). However, there was no history of such exposure in any of the parents of our patients.…”

“…Congenital complex chromosome rearrangement (CCR) is defined as a congenital chromosome aberration involving three or more break points and with reciprocal exchange of segments between two or more chromosomes (Kousseff et al, 1987). It has been classified into two groups: familial and de novo.…”

“…Among some 60 CCRs reported, about half are familial and half are de novo (Pai et al, 1980). De novo CCRs involving five or more break points are infrequent, having been reported in only 17 cases (Fukushima et al, 1986;Kousseff et al, 1987).…”

Les remaniements chromosomiques complexes

“…Cette première classification a révélé une nette prévalence de l'origine maternelle des CCR hérités. En 1987, Kousseff et al [3] proposèrent de classer les CCR en fonction du nombre de points de cassure. Cette classification met ainsi en évi-dence le fait que les anomalies transmises au travers des générations sont de plus faible complexité (avec moins de cinq points de cassure) que celles qui apparaissent de novo et qui font intervenir un nombre plus élevé de points de cassure.…”

Constitutional complex chromosomal rearrangements in a klinefelter patient: case report and review of literature

“…CCRs can be classified based on the number of chromosome breaks: those with four or fewer breaks (mainly seen in balanced female carriers), and those with more than four breaks (mostly detected in de novo CCRs) [7].…”