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Hurd LM, Thacker MM, Okenfuss E, Duker AL, Lou Y, Harty MP, Conard K, Lian JB, Bober MB. Aneurysmal bone cysts and pathologic fracture associated with supernumerary ring chromosome 6 in two unrelated patients. Am J Med Genet A 2017; 173:3205-3210. [PMID: 29080333 DOI: 10.1002/ajmg.a.38498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 08/07/2017] [Accepted: 09/15/2017] [Indexed: 11/08/2022]
Abstract
Small supernumerary ring chromosome 6 (sSRC[6]) is a rare chromosomal abnormality characterized by a broad clinical phenotype. The spectrum of this disorder can range from phenotypically normal to severe developmental delay and congenital anomalies. We describe two unrelated patients with small SRCs derived from chromosome 6 with a novel bone phenotype. Both patients presented with a complex bone disorder characterized by severe osteopenia, pathologic fractures, and cyst-like lesions within the bone. Imaging revealed decreased bone mineral density, mutiple multiloculated cysts and cortical thinning. Lesion pathology in both patients demonstrated a bland cyst wall with woven dysplastic appearing bone entrapped within it. In patient 1, array comparative genomic hybridization (CGH) detected a tandem duplication of region 6p12.3 to 6q12 per marker chromosome. Cytogenetic analysis further revealed a complex patient of mosaicism with some cell lines displaying either one or two copies of the marker indicative of both tetrasomy and hexasomy of this region. Patient 2 was mosaic for a sSRC that encompassed a 26.8 Mb gain from 6p21.2 to 6q12. We performed an in-depth clinical analysis of a phenotype not previously observed in sSRC(6) patients and discuss the potential influence of genes located within this region on the skeletal presentation observed.
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Affiliation(s)
- Lauren M Hurd
- Department of Biomedical Research, Nemours-Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Mihir M Thacker
- Department of Orthopaedic Surgery, Nemours-Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Ericka Okenfuss
- Department of Genetics, Skeletal Dysplasia Program, Kaiser Permanente, Oakland, California
| | - Angela L Duker
- Division of Medical Genetics, Nemours-Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Yang Lou
- Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, Massachusetts.,Yurogen Biosystems LLC., Worcester, Massachusetts
| | - Mary P Harty
- Department of Medical Imaging, Nemours-Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Katrina Conard
- Department of Pathology, Nemours-Alfred I. duPont Hospital for Children, Wilmington, Delaware
| | - Jane B Lian
- Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, Massachusetts.,Department of Biochemistry, Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Michael B Bober
- Division of Medical Genetics, Nemours-Alfred I. duPont Hospital for Children, Wilmington, Delaware
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Huang B, Pearle P, Rauen KA, Cotter PD. Supernumerary marker chromosomes derived from chromosome 6: cytogenetic, molecular cytogenetic, and array CGH characterization. Am J Med Genet A 2012; 158A:1568-73. [PMID: 22639445 DOI: 10.1002/ajmg.a.35385] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Accepted: 03/05/2012] [Indexed: 11/10/2022]
Abstract
Supernumerary marker chromosomes (SMC) are relatively common in prenatal diagnosis. As the clinical outcomes vary greatly, a better understanding of the karyotype-phenotype correlation for different SMCs will be important for genetic counseling. We present two cases of prenatally detected de novo, small SMCs. The markers were present in 80% of amniocyte colonies in Case 1 and 38% of the colonies in Case 2. The SMCs were determined to be derived from chromosome 6 during postnatal confirmation studies. Although the sizes and the chromosomal origin of the SMCs in these two cases appeared to be similar, the clinical outcomes varied. The clinical manifestations observed in Case 1 included small for gestational age, feeding difficulty at birth, hydronephrosis, deviated septum and dysmorphic features, while the phenotype is apparently normal in Case 2. Array comparative genomic hybridization (CGH) was performed and showed increase in dosage for approximately 26 Mb of genetic material from the proximal short and long arms of chromosome 6 in Case 1. Results of array CGH were uninformative in Case 2, either due to mosaicism or lack of detectable euchromatin. The difference in the clinical presentation in these two patients may have resulted from the difference in the actual gene contents of the marker chromosomes and/or the differential distribution of the mosaicism.
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Affiliation(s)
- Bing Huang
- Integrated Genetics, Monrovia, California 91016, USA.
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Chromosome 5 derived small supernumerary marker: towards a genotype/phenotype correlation of proximal chromosome 5 imbalances. J Appl Genet 2011; 52:193-200. [PMID: 21437654 DOI: 10.1007/s13353-011-0035-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 02/11/2011] [Accepted: 02/15/2011] [Indexed: 12/12/2022]
Abstract
Small supernumerary marker chromosomes (sSMC) are a morphological heterogeneous group of additional abnormal chromosomes that cannot be characterized alone by conventional banding cytogenetics. Molecular cytogenetic techniques are valuable tools for the accurate identification of sSMC and a prerequisite for sound genetic counseling based on refined genotype/phenotype correlation. We describe a new case of a retarded patient with an sSMC derived from chromosome 5. The characterization of the sSMC was done by subcentromere-specific multicolor (subcenM) fluorescence in-situ hybridization (FISH) and by full tilling resolution array analysis, after microdissection and amplification of the marker DNA. Uniparental disomy for normal sister chromosomes of the sSMC(5) was excluded. The karyotype was mos47,XX,+r(5)(::p11.1 → q12.1::)[70%]/46,XX[30%], being the trisomic region between 46.15 ∼ 49.56 Mb and 61.25 ∼ 61.335 Mb, a region known to harbor ∼45 annotated genes. Together with a review of the previously described cases of sSMC(5) and duplications involving the 5q proximal region, we can conclude that trisomy of the 5q11 region is associated with learning difficulties and speech delay.
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Fickelscher I, Starke H, Schulze E, Ernst G, Kosyakova N, Mkrtchyan H, MacDermont K, Sebire N, Liehr T. A further case with a small supernumerary marker chromosome (sSMC) derived from chromosome 1--evidence for high variability in mosaicism in different tissues of sSMC carriers. Prenat Diagn 2007; 27:783-5. [PMID: 17546703 DOI: 10.1002/pd.1776] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A prenatally ascertained case with a de novo small supernumerary marker chromosome (sSMC) derived from chromosome 1 is reported. Due to a fetal heart defect the parents decided in favour of an induced abortion. Postmortem, a molecular cytogenetic study on eleven formalin fixed, paraffin-embedded tissues of the fetus was performed, to further characterize the levels of mosaicism of the sSMC(1). sSMC presence varied between 13 and 62% within different tissues of sSMC carriers. This finding is something common in sSMC carriers and could explain why up to the present no clinical correlations for sSMC mosaicism and clinical outcome in the corresponding carriers could be established.
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Affiliation(s)
- Ina Fickelscher
- Institute of Human Genetics and Anthropology, Kollegiengasse 10, Jena, Germany
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Bibliography. Current world literature. Maternal-fetal medicine. Curr Opin Obstet Gynecol 2007; 19:196-201. [PMID: 17353689 DOI: 10.1097/gco.0b013e32812142e7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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