biostudies-literatureKaramysheva TVRussian Foundation for Basic ResearchE1511https://www.ebi.ac.uk/biostudies/studies/S-EPMC7766715biostudies-literatureUnknown11(12)For medical genetic counseling, estimating the chance of a child being born with chromosome abnormality is crucially important. Cytogenetic diagnostics of parents with a balanced karyotype are a special case. Such chromosome rearrangements cannot be detected with comprehensive chromosome screening. In the current paper, we consider chromosome diagnostics in two cases of chromosome rearrangement in patients with balanced karyotype and provide the results of a detailed analysis of complex chromosomal rearrangement (CCR) involving three chromosomes and a small supernumerary marker chromosome (sSMC) in a patient with impaired reproductive function. The application of fluorescent in situ hybridization, microdissection, and multicolor banding allows for describing analyzed karyotypes in detail. GenesTwo Separate Cases: Complex Chromosomal Abnormality Involving Three Chromosomes and Small Supernumerary Marker Chromosome in Patients with Impaired Reproductive Function.PMC776671519-015-00084aMuzyka VVGayner TAOrishchenko KEKaramysheva TVRubtsov NBfalseTwo Separate Cases: Complex Chromosomal Abnormality Involving Three Chromosomes and Small Supernumerary Marker Chromosome in Patients with Impaired Reproductive Function.For medical genetic counseling, estimating the chance of a child being born with chromosome abnormality is crucially important. Cytogenetic diagnostics of parents with a balanced karyotype are a special case. Such chromosome rearrangements cannot be detected with comprehensive chromosome screening. In the current paper, we consider chromosome diagnostics in two cases of chromosome rearrangement in patients with balanced karyotype and provide the results of a detailed analysis of complex chromosomal rearrangement (CCR) involving three chromosomes and a small supernumerary marker chromosome (sSMC) in a patient with impaired reproductive function. The application of fluorescent in situ hybridization, microdissection, and multicolor banding allows for describing analyzed karyotypes in detail. 2020-01-01T00:00:00Z2020 Dec2025-04-22T08:44:48.376Z2025-04-05T22:38:22.291ZS-EPMC77667153334859010.3390/genes11121511