Related Experiment Video
Updated: Aug 16, 2026

Spectral Karyotyping to Study Chromosome Abnormalities in Humans and Mice with Polycystic Kidney Disease
Published on: February 3, 2012
Unusual small supernumerary marker chromosome (sSMC) 9 in a Klinefelter patient
1Institut fur Humangenetik und Anthropologie, Jena, Germany. i8lith@mti.uni-jena.de
Abstract:
Small supernumerary marker chromosomes (sSMC) are small additional chromosomes characterizable for their origin only by molecular cytogenetic approaches. sSMC have been reported previously in four types of syndromes associated with chromosomal imbalances: in approximately 150 cases with Turner syndrome, 26 cases with Down syndrome and only one case each with Klinefelter syndrome and "Triple-X"-syndrome. Here we report the second case with an sSMC detected in addition to a Klinefelter karyotype. Molecular cytogenetics applying centromere-specific multicolor FISH (cenM-FISH) and a specific subcentromere-specific (subcenM-FISH) probe set characterized the sSMC as a dic(9)(:p12-->q11.1::q11.1--> p11.1:). The reported patient was described with hypogonadism, gynaecomastia plus a bronchial carcinoma. The patient's clinical features are discussed in connection with other Klinefelter cases and possible consequences of presence of the sSMC(9). Furthermore, a suggestion is made for the mode of sSMC-formation in this case.
Related Concept Videos
Karyotyping
Nondisjunction
Nondisjunction
The Y Chromosome Determines Maleness
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size. Today,...
X-Inactivation
Inheritance of Chromatin Structures

