Small supernumerary marker chromosomes derived from human chromosome 11.

With only 39 reported cases in the literature, carriers of a small supernumerary marker chromosome (sSMC) derived from chromosome 11 represent an extremely rare cytogenomic condition. Herein, we present a review of reported sSMC(11), add 18 previously unpublished cases, and closely review eight cases classified as 'centromere-near partial trisomy 11' and a further four suited cases from DECIPHER. Based on these data, we deduced the borders of the pericentric regions associated with clinical symptoms into a range of 2.

How to Obtain High-Quality Metaphase Spreads for Molecular Cytogenetics.

Interphase or metaphase nuclei can be accessed in molecular cytogenetic analyses. Metaphase spreads are routinely studied by fluorescence in situ hybridization (FISH) to answer clinical genetic questions. Even though metaphase quality is essential for FISH studies, there is limited ability in clinical cases to improve the quality of cytogenetic preparations.

The acrocentric part of der(Y)t(Y;acro)(q12;p1?2) contains D15Z1 sequences in the majority of cases.

Chromosomal heteromorphisms (CHMs) are currently largely disregarded in human genetic diagnostics. One exception is der(Y)t(Y;acro)(q12;p1?2), which has at least been mentioned in karyotypes and discussed in reports. This derivative is frequently observed in healthy males with idiopathic infertility, which is not uncommon for CHMs.