Several studies claim to have demonstrated an increased frequency of Down syndrome (DS) dermatoglyphics and other DS characteristics in parents of DS children, which could be explained by unrecognized parental mosaicism for trisomy 21. The goal of this study was to test the following hypothesis: In some cases of DS the cause will be parental gonadal mosaicism for trisomy 21. These parents will also be mosaic in tissues other than the gonads and will therefore have quantitative deviations in the direction of the DS phenotype. Upon examination of such traits in 162 parents with one DS child it was found that 22 parents had dermatoglyphic characteristics within the DS distribution of the Preus diagnostic index (no significant increase), 6 had DS quantitative phenotypic traits, and 1 had both. There was no evidence of bimodality in the distribution of these traits, or of a correlation between these traits with one another or with the Preus dermatoglyphic index for DS. There were no trisomy 21 cells in 200 lymphoblast cells counted for each of the 5 subjects with the most DS-like dermatoglyphic characteristics. The one subject who has both DS dermatoglyphics and a trend toward DS phenotype had 1/300 trisomy 21 cells in lymphoblast culture and 0/100 cells in fibroblast culture. Neither these data nor these from the literature, provide support for the suggestion that parental mosaicism for trisomy 21 is associated with an increase in DS-like physical characteristics.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.61199 |
| Date | January 1991 |
| Creators | Gilbert, Adel Dorothy |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001275710, proquestno: AAIMM74882, Theses scanned by UMI/ProQuest. |
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