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Supernumerary marker chromosomes detected in 100 000 prenatal diagnoses: molecular cytogenetic studies and clinical significance
Author(s) -
Huang Bing,
Solomon Sharon,
Thangavelu Maya,
Peters Katherine,
Bhatt Sucheta
Publication year - 2006
Publication title -
prenatal diagnosis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.956
H-Index - 97
eISSN - 1097-0223
pISSN - 0197-3851
DOI - 10.1002/pd.1575
Subject(s) - small supernumerary marker chromosome , uniparental disomy , supernumerary , marker chromosome , biology , fluorescence in situ hybridization , centromere , prenatal diagnosis , chromosome , angelman syndrome , clinical significance , genetics , cytogenetics , chromosome 15 , karyotype , pathology , fetus , medicine , pregnancy , gene , anatomy
Objective To evaluate the clinical significance of the supernumerary marker chromosomes (SMCs) detected during prenatal diagnosis. Methods We retrospectively studied cytogenetic/fluorescence in situ hybridization (FISH) results and clinical evaluation of 110 marker cases identified from ∼100 000 cases referred for prenatal diagnosis. The clinical follow‐up performed was focused on cases with de novo markers not derived from chromosome 15. Results Among the 110 SMCs, 79 (71.8%) were de novo , 24 (21.8%) were familial, and the origin was undetermined in 7 cases. Fifty‐eight of the SMCs originated from nonacrocentric chromosomes and 52 SMCs were derived from acrocentric chromosomes, with 27 originating from chromosome 15. Twenty‐two of the SMCs from chromosome 15 did not contain the Prader‐Willi/Angelman syndrome critical region, and uniparental disomy was ruled out in 19/19 cases. Clinical information ranging from birth to 4 years was obtained for 46 de novo cases with nonchromosome‐15‐derived SMCs. Of these cases, 11/11 acrocentric SMCs resulted in normal phenotype. In contrast, 4/23 cases with single nonacrocentric SMCs and 3/5 cases with two or more SMCs resulted in an abnormal phenotype. Conclusions Our data suggests an overall low risk for acrocentric SMCs and a higher risk for nonacrocentric SMCs. Phenotypes associated with markers derived from some specific chromosomes are also discussed. Copyright © 2006 John Wiley & Sons, Ltd.