Balanced chromosome rearrangements and abnormal phenotype.

Abstract

Analysis of the results of 3411 routine cytogenetic examinations initiated by abnormal phenotype or family history revealed that out of 44 cases with balanced structural aberration 12 patients had an abnormal phenotype. Of the 12 cases, there were four reciprocal translocations, three Robertsonian translocations, and five pericentric inversions. Eight rearrangements were inherited, one had occurred de novo, and three were of unknown origin. Each carrier parent was apparently healthy. In all of the four cases with reciprocal translocation the rearrangements were of paternal origin. None of the clinical abnormalities could be assigned specifically to the breakpoints. Explaining the association of balanced chromosomal rearrangement and clinical abnormalities, possibilities of causal relationship and by chance coincidence are discussed.