Free proximal trisomy 21 without the Down syndrome |
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| Authors: | Jonathan P Park Doris H Wurster-Hill Patricia A Andrews William C Cooley John M Graham Jr |
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| Institution: | Department of Pathology, Dartmouth-Hitchcock Medical Center, Hanover, New Hampshire. |
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| Abstract: | Analysis of partial duplication of chromosome 21 suggests that band 21q22 contains determinants for the Down syndrome. We report two cases of free proximal trisomy 21 without manifestations of the Down syndrome. Phenotypic anomalies included marked microcephaly, short stature, hypoplastic nails, and mental retardation/developmental delay. Our cases are consistent with the assignment of band 21q22 as the causal duplicated segment in the Down syndrome. |
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| Keywords: | chromosome 21 double NOR Down syndrome microcephaly trisomy 21 |
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