In a series of 374 families with Down syndrome progeny, structural chromosome rearrangements were detected in the parents of six children with regular trisomy. The aberrations were reciprocal translocations and inversions. In all three informative families, the parent who transmitted the extra chrom
Trisomy 21 Down syndrome
β Scribed by Irene A. Uchida; Viola C. P. Freeman
- Publisher
- Springer
- Year
- 1985
- Tongue
- English
- Weight
- 311 KB
- Volume
- 70
- Category
- Article
- ISSN
- 0340-6717
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β¦ Synopsis
The lymphocyte chromosomes of trisomy 21 Down syndrome patients and their parents in a random series of 374 families were analyzed, the objective being the identification of parental mosaicism. The numbers of parents in whom at least two trisomy 21 cells were detected were seven mothers and three fathers, a frequency of 2.7% of families. Confirmation of mosaicism was by identification of parental transmission of the extra chromosome to the progeny, by repeat chromosome analysis, and/or by the presence of more than one affected child. If to these are added six others in whom only one trisomic cell was detected, but with no other supporting evidence, the frequency could be as high as 4.3%. Differences in parental age at the birth of Down syndrome progeny may be accounted for by differences in frequencies of mosaicism in germ cells and somatic tissue. Mosaicism was found more frequently in the mothers than in the fathers, but more data are required for confirmation of a real difference.
π SIMILAR VOLUMES
A hypothesis relating interferon action and the chromosome 21 trisomy genotype and phenotype was presented in this journal in 1980. Since that time a number of additional genes involved in interferon action have been mapped to the distal Down Syndrome region of chromosome 21 and a growing literature