Confirmation of trisomy 22 by trypsin-giemsa staining.
(25/236)
A small-for-dates male infant with mental retardation, microcephaly, malformed ears, preauricular sinuses, epicanthal folds, micrognathia, congenital heart diseases, micropenis, and micropolygyria of the parietal and occipital lobes of the cerebral cortex was shown to have a 47,XY,+22 karyotype by trypsin-giemsa banding. Review of reported cases confirms that there may be distinctive trisomy 22 syndrome. (+info)
A fluorescence polymorphism associated with Down's syndrome?
(26/236)
Fluorescence polymorphism frequencies have been determined for a group of 85 Down's syndrome cases and 164 controls. For one class of polymorphism, that of positive satellites of chromosome 21, the frequency in the Down's cases was significantly higher than in the controls; the distribution of positive satellites in the mongols indicates that in the majority the extra chromosome arose by first meiotic non-disjunction. The possibility that positive satellites on chromosome 21 could be a causative factor in Down's syndrome is discussed, and the implications of this possibility on the assessment of the risk of producing a Down's child are examined. (+info)
Down's syndrome and deletion of short arms of a G chromosome.
(27/236)
A woman in a family in which a G group chromosome (No. 21) with deleted short arms (21p-) is present has passed this chromosome to an intellectually deficient son, a normal son, and a daughter with Down's syndrome. Another daughter is chromosomally and phenotypically normal. As in other reports that focus on a concurrence of Gp- chromosomes and Down's anomaly, the possibility is considered that this chromosomal variant may predispose to developmental abnormalities or to non-disjunction, or both. (+info)
Reproduction in a woman with low percentage t(21q21q) mosaicism.
(28/236)
The birth of a child is described with Down syndrome followed by the conception of a fetus bearing the t(21q21q) chromosome in 100% of their cells in a women mosiac for the translocation in less than 10% of 2 of her examined tissues and in none of the cells in her peripheral blood. Various hypotheses for explaining the above findings are discussed. The importance of examining as many parental tissues as possible for the detection of low percentage mosiacism is stressed. (+info)
Regular G21-trisomy in 3 sibs from mother with trisomy 21 mosaicism.
(29/236)
This paper describes a family with 3 affected sibs with regular trisomy 21 Down syndrome. The condition seems to be transmitted from a phenotypically normal mother in whom G-trisomy mosaicism was identified. Giemsa banding depicted trisomy 21 mosaicism in cells from the mother. Chromosomes from the children showed a trisomy 21 in all the cells analysed. (+info)
Dosage effects for superoxide dismutase-1 in nucleated cells aneuploid for chromosome 21.
(30/236)
Assays of the activity of chromosome 21 determined superoxide dismutase-1 (SOD-1) in lymphocytes and polymorphonuclear granulocytes have demonstrated 38% and 40% increases, respectively, in cells from individuals with trisomy 21. Similarly, SOD-1 activity in trisomic fibroblasts is increased by 81%, while cells monosomic for chromosome 21 have only 60% of normal activity. Taken together with the data on SOD-1 activities in trisomic erythrocytes and platelets, the present results firmly confirm the existence of a true dosage effect for this enzyme in cells aneuploid for chromosome 21. However, the results of assays of the activity of glutathione peroxidase in trisomic fibroblasts did not confirm the possibility previously reported of a chromosome 21 related dosage effect for this enzyme. (+info)
Report of large kinship with familial translocation between chromosomes 21 and 22.
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This paper reports a large kinship with a familial (21;22) translocation occurring in both the balanced and the unbalanced states. Recurrence risks for the (21;22) translocation in the unbalanced state are high (14%) for the offspring of female carriers as compared with those for the offspring of male carriers (4%), but the offspring of male carriers appear to have a much higher risk (50%) of being balanced carriers than those of female carriers (30%). (+info)
Familial balanced translocation 4p+/17q- as a suggested cause of primary trisomy-21 Down's syndrome.
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A case is presented in which a 4p+/17q- familial balanced reciprocal translocation in the mother produced a son with primary trisomy-21, as well as the structural chromosomal anomaly. A number of similar situations have been reported, suggesting that the two events are related. In practice, this (as well as other direct risks) should be taken into account when counseling those families in which one parent carries a balanced translocation. A hypothesis, based on experiments in Drosophila, has been put forward by Grell to explain the mechanism which links the balanced structural abnormality to an aneuploidy of chromosomes not taking part in the structural change, and this has been extended to similar human situations. (+info)