## Abstract UllrichโTurner syndrome (UTS) is most commonly due to a 45,X chromosome defect, but is also seen in patients with a variety of Xโchromosome abnormalities or 45,X/46,XY mosaicism. The phenotype of UTS patients is highly variable, and depends largely on the karyotype. Patients are at an i
Mosaic down syndrome in a patient with low-level mosaicism detected by microarray
โ Scribed by Eyby Leon; Ying S. Zou; Jeff M. Milunsky
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 142 KB
- Volume
- 152A
- Category
- Article
- ISSN
- 1552-4825
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โฆ Synopsis
Abstract
Down syndrome (DS) is the most common aneuploidy in liveborns with an estimated frequency of 1 in 650โ1,000 births. Approximately 1โ2% of all liveโborn DS individuals have mosaicism. The correlation between the percentage of mosaicism and the severity of the phenotype in mosaic trisomy 21 has been determined in previous studies. Patients with low percent of trisomy 21 have less phenotypic manifestations, higher IQs, and better overall survival. We report on a 1โdayโold baby girl with subtle features of DS and lowโlevel trisomy 21 mosaicism (8โ13% in lymphocytes, 31% in buccal cells) with normal high resolution chromosome analysis. The aneuploidy was detected by 6.0 SNP microarray and confirmed by fluorescent in situ hybridization (FISH). Further studies to detect mosaicism are recommended from blood (using interphase FISH) or other tissues in the evaluation of a child with features of DS and a normal blood metaphase karyotype. SNP microarray technology appears to be a useful adjunct, being able to detect lowโlevel mosaicism in these cases. ยฉ 2010 WileyโLiss, Inc.
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During a study of the familial aggregation of Down syndrome (DS) and Alzheimer disease (AD), we observed an increase in mosaicism for disomy 21 in older individuals with DS. In a total of 213 DS subjects who were studied cytogenetically, only 1 of 121 (0.8%) under age 45 exhibited mosaicism, while 1
## Abstract Genetic mosaicism is the presence of genetically different cell populations within an individual and can be associated with a milder disease phenotype. We describe a somatic mosaicism in a Lynch syndrome patient with a __MLH1__ gene mutation (c.1050delA). Since she was the sister of a h