A 14-year follow-up of a case detected prenatally of partial trisomy 13q21.32-qter and monosomy 18q22.3-qter as a result of a maternal complex chromosome rearrangement involving chromosomes 6, 13, and 18

Abstract

A balanced complex chromosome rearrangement (CCR) involving three chromosomes is rare and may lead to different types of aneuploid germ cells. We report here a 14-year follow-up of a boy with a karyotype defined as 46,XY,der(18)t(6;13;18)(q21;q21.32;q22.3).ish der(18)(13qter+,18qter-) characterized by multiple congenital abnormalities, including distinctive minor facial anomalies, short neck, abnormalities of the extremities, anogenital abnormalities, flexion contractures, especially at extremities, and severe mental and growth retardation. Chromosome analysis in the mother showed a CCR involving chromosomes 6, 13, and 18. This CCR was the result of a three-break rearrangement, and the derivative chromosome 13 consisted of parts of chromosomes 18 and 13. The karyotype of the child was not balanced, and resulted in partial trisomy for 13q and partial monosomy for 18q detected prenatally by conventional and molecular cytogenetics. Although such a karyotype and its phenotype have not previously been reported, we have compared the clinical and cytogenetic data from our patient with previously described cases of partial trisomy 13q and monosomy 18q despite different break points. We are presenting a new CCR in a woman with normal phenotype with a history of four early abortions and a long follow-up of her malformed newborn with partial 13q trisomy and 18q monosomy.