Rearrangements of the region 1q42.13q43 are rare, with only 7 cases reported to date. The imbalances described are usually the result of inherited translocations with other chromosomes. Moreover, few cases of both inter- and intrachromosomal deletions/duplications detected cytogenetically have been described. We report the molecular cytogenetic characterization of an inverted insertion involving the region 1q42.13q43 and segregating in 2 generations of a family. The deletion and the duplication of the same segment were detected in 2 affected family members. SNP array analysis showed the familial origin of the deletion/duplication due to the occurrence of a crossing-over during meiosis. Our report underlines the importance of determining the correct origin of chromosomal aberrations using different molecular cytogenetic tests in order to provide a good estimation of the reproductive risk for the members of the family.