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 Herein, we present a review of reported sSMC(11), add 18 previously unpublished cases, and closely review eight cases classified as 'centromere-near partial trisomy 11' and a further four suited cases from DECIPHER.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.

Small supernumerary marker chromosomes derived from chromosome 14 and/or 22.

Small supernumerary marker chromosomes (sSMCs) are additional derivative chromosomes present in an otherwise numerically and structurally normal karyotype. They may derive from each of the 24 human chromosomes, and most contain a normal centromeric region with an alphoid sequence from a single chromosome. The majority of human chromosomes have a unique centromeric DNA-sequence enabling their indubitable characterization.

Molecular cytogenetic pilot study on pleomorphic adenomas of salivary glands.

Pleomorphic adenomas (PAs) of salivary glands are the most frequent entity of solid parotid tumors. Nonetheless, their genetics is not yet well understood. Thus, the current study characterized 14 PAs using a unique combination of cytogenetic, molecular cytogenetic and/or molecular karyotyping based approaches.

Recombinant Chromosomes Resulting From Parental Pericentric Inversions-Two New Cases and a Review of the Literature.

A balanced pericentric inversion is normally without any clinical consequences for its carrier. However, there is a well-known risk of such inversions to lead to unbalanced offspring. Inversion-loop formation is the mechanism which may lead to duplication or deletion of the entire or parts of the inverted segment in the offspring.

Assessing Skewed X-Chromosome Inactivation.

We describe a simple and straightforward method for detection and characterization of X-chromosome inactivation in females and/or individuals with more than one X chromosome. The X-chromosome inactivation pattern is visualized on a single-cell level using 5-ethynyl-2-deoxyuridine (EdU) instead of the previously widely applied 5-bromo-2'-deoxyuridine (BUdR). The fluorochrome-labeled nucleoside analog EdU is incorporated into late-replication chromosomal regions of living blood cells in vitro; thus, it can also be used to specifically highlight the inactive X chromosome within a cytogenetic preparation.

A Girl with 10 Mb Distal Xp Deletion Arising from Maternal Pericentric Inversion: Clinical Data and Molecular Characterization.

Background: Short arm deletions of the X-chromosome are challenging issues for genetic counseling due to their low penetrance in population. Female carriers of these deletions have milder phenotype than male ones, considering the intellectual ability and social skills, probably because of the X-chromosome inactivation phenomenon.

Case Report: A female patient with a 10Mb distal Xp deletion and an Xq duplication, showing mild intellectual disability, is described in this report.

Parental origin of deletions and duplications - about the necessity to check for cryptic inversions.

Background: Copy number variants (CNVs) are the genetic bases for microdeletion/ microduplication syndromes (MMSs). Couples with an affected child and desire to have further children are routinely tested for a potential parental origin of a specific CNV either by molecular karyotyping or by two color fluorescence in situ hybridization (FISH), yet. In the latter case a critical region probe (CRP) is combined with a control probe for identification of the chromosome in question.

Unusual de novo Partial Trisomy 17p12p11.2 due to Unbalanced Insertion into 5p13.1 in a Severely Affected Boy.

Gain of copy numbers can be due to different chromosomal rearrangements such as direct or indirect duplications, translocations, small supernumerary marker chromosomes, or insertions. In a 3-year-old boy with dysmorphic features and developmental delay, chromosome analyses revealed a derivative chromosome 5. Microdissection and reverse fluorescence in situ hybridization identified the in 5p13.

Complex Rearrangement Involving Three Chromosomes, Four Breakpoints and a 2.7-Mb Deletion in the 18q Segment Observed in a Girl with Mild Learning Difficulties.

Complex chromosomal rearrangements (CCRs) are balanced or unbalanced structural rearrangements involving 3 or more cytogenetic break events on 2 or more different chromosomes. Here, we report a 7-year-old girl referred to our unit because of mild dysmorphic facial features, mild learning difficulties together with very mild mental retardation. Standard cytogenetic banding analysis revealed a de novo CCR involving chromosomes 1, 2 and 18.

De novo 393 kb microdeletion of 7p11.2 characterized by aCGH in a boy with psychomotor retardation and dysmorphic features.

We report on a 27 month old boy presenting with psychomotor delay and dysmorphic features, mainly mild facial asymmetry, prominent cup-shaped ears, long eyelashes, open mouth appearance and slight abnormalities of the hands and feet. Array comparative genomic hybridization revealed a 393 kb microdeletion in 7p11.2.

Mitotic stability of small supernumerary marker chromosomes depends on their shape and telomeres - a long term in vitro study.

Mosaicism is present in more than 50% of the cases with small supernumerary marker chromosomes (sSMCs) and karyotype 47,XX,+mar/46,XX or 47,XY,+mar/46,XY. Recently we provided first evidence that the mitotic stability of sSMC is dependent on their structure, i.e.

An interstitial 4q31.21q31.22 microdeletion associated with developmental delay: case report and literature review.

The 4q deletion syndrome phenotype consists of growth failure and developmental delay, minor craniofacial dysmorphism, digital anomalies, and cardiac and skeletal defects. We have identified an inversion (inv(1)(q25.2q31.

Mitotic stability of small supernumerary marker chromosomes: a study based on 93 immortalized cell lines.

Small supernumerary marker chromosomes (sSMC) are known for being present in mosaic form as 47,+mar/46 in >50% of the cases with this kind of extra chromosomes. However, no detailed studies have been done for the mitotic stability of sSMC so far, mainly due to the lack of a corresponding in vitro model system. Recently, we established an sSMC-cell bank (Else Kröner-Fresenius-sSMC-cellbank) with >150 cell lines.

Prenatal diagnosis of proximal partial trisomy 1q confirmed by comparative genomic hybridization array: molecular cytogenetic analysis, fetal pathology and review of the literature.

Background: Partial trisomy of the long arm of chromosome 1 (1q) is an exceptionally rare chromosomal abnormality and most of the prenatally diagnosed cases are associated with either complete (q11-qter) or large (q21-qter) duplications with pre- or perinatal demise of all reported cases. The most common sonographic findings associated with this karyotype abnormality include ventriculomegaly, increased nuchal translucency or nuchal fold, renal and cardiac abnormalities, craniofacial dysmorphism, and limb deformities. However, there is a wide spectrum of clinical manifestations due to the great variability in the extent of the duplication size and the possible contribution of additional genetic rearrangements in the final phenotype.

Proximal 10q duplication in a child with severe central hypotonia characterized by array-comparative genomic hybridization: A case report and review of the literature.

Proximal 10q duplication is a well-defined but rare genetic syndrome. Duplication of proximal segments of the long arm of chromosome 10 results in a pattern of malformations, which are distinct from those of the more common distal 10q trisomy syndrome. The present study describes the case of a boy with phenotypic abnormalities (severe central hypotonia, mild ataxia, moderate developmental delay and mild dysmorphic features), due to duplication of chromosome region, 10q11.

Complex small supernumerary marker chromosomes - an update.

Background: Complex small supernumerary marker chromosomes (sSMC) constitute one of the smallest subgroups of sSMC in general. Complex sSMC consist of chromosomal material derived from more than one chromosome; the best known representative of this group is the derivative chromosome 22 {der(22)t(11;22)} or Emanuel syndrome. In 2008 we speculated that complex sSMC could be part of an underestimated entity.

A new multicolor fluorescence in situ hybridization probe set directed against human heterochromatin: HCM-FISH.

A new multicolor fluorescence in situ hybridization (mFISH) probe set is presented, and its possible applications are highlighted in 25 clinical cases. The so-called heterochromatin-M-FISH (HCM-FISH) probe set enables a one-step characterization of the large heterochromatic regions within the human genome. HCM-FISH closes a gap in the now available mFISH probe sets, as those do not normally cover the acrocentric short arms; the large pericentric regions of chromosomes 1, 9, and 16; as well as the band Yq12.

New cytogenetically visible copy number variant in region 8q21.2.

Background: Cytogenetically visible unbalanced chromosomal abnormalities (UBCA), reported for >50 euchromatic regions of almost all human autosomes, are comprised of a few megabases of DNA, and carriers are in many cases clinically healthy. It may be speculated, that some of the UBCA may be similar or identical to copy number variants (CNV) of the human genome.

Results: Here we report on a yet unreported cytogenetically visible copy number variant (CNV) in the long arm of chromosome 8, region 8q21.

Duplication 4q associated with chronic cholestatic changes in liver biopsy.

We report a 15-day-old girl with partial trisomy 4q syndrome who presented with neonatal cholestasis. She had dysmorphic facial features and preaxial polysyndactyly of the right hand. The other findings were generalized hypertrichosis, pes equinovarus, oedema on feet and mild hepatomegaly.

Four small supernumerary marker chromosomes derived from chromosomes 6, 8, 11 and 12 in a patient with minimal clinical abnormalities: a case report.

Introduction: Small supernumerary marker chromosomes are still a problem in cytogenetic diagnostic and genetic counseling. This holds especially true for the rare cases with multiple small supernumerary marker chromosomes. Most such cases are reported to be clinically severely affected due to the chromosomal imbalances induced by the presence of small supernumerary marker chromosomes.

Prenatal detection of full monosomy 21 in a fetus with increased nuchal translucency: molecular cytogenetic analysis and review of the literature.

Full monosomy 21 is an extremely rare chromosomal disorder. A 38-year-old woman attended a first trimester scan. Ultrasound (U/S) imaging of the fetus at 12 weeks of gestation showed features of increased nuchal translucency measurement (12 mm).

Small supernumerary marker chromosomes 1 with a normal phenotype.

Small supernumerary marker chromosomes (sSMCs) are a major problem in prenatal cytogenetic diagnostics. Over two-thirds of cases carrying an sSMC derived from chromosome 1 are associated with clinical abnormalities. We report 3 further cases of such sSMCs that did not show any clinical abnormalities.