A child with a 21-ring chromosome, 45,XX,21-/46,XX,21r investigated with the banding technique

Summary Chromosomal analysis of lymphocytes and fibroblasts in a slightly retarded 7-month-old female infant with some minor malformations showed a mosaicism 45,XX,G-/46,XX,Gr. The ring chromosome was identified as No. 21 by banding technique.

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Zusammenfassung Chromosomenuntersuchungen an Lymphocyten und Fibroblasten bei einem 7 Monate alten Mädchen mit leichter statomotorischer Entwicklungsverzögerung und degenerativen Stigmata zeigten ein Mosaik 45,XX,G-/46,XX,Gr. Durch die Bandentechnik mit Trypsinbehandlung konnte das Ringchromosom als Nr.21 identifiziert werden.

     

46,XX,t(15;21)/47,XX,15p-,+21 mosaicism in a child with Down's syndrome

We report here the first case of a mosaic Down's syndrome in which both clones are trisomic for chromosome 21, one of them (90%) by a Robertsonian translocation (15;21) appearing de novo, and the other (10%) by an additional chromosome 21. Three hypotheses can explain the appearance of such a mosaic: that of a chimera formed by the fusion of two trisomy 21 zygotes, one of which had a Robertsonian translocation, the other an additional trisomy 21 zygote; that of a fusion between a chromosome 15 and a chromosome 21 in one of the early segmentation blastomeres of a trisomy 21 zygote; the more probable hypothesis of the occurrence of a fission at the break-attachment point of a Robertsonian translocation (15;21) in one of the cells arising from the early postzygotic divisions of a zygote which was a trisomy 21 by Robertsonian translocation (15;21).     

新生儿缺氧性脑病伴46,XX,-21,+t(21;21)罕见核型一例

Abstract:This report describes a cytogenetic aberration in one neonatal patient with hypoxic-ischemic encephalopathy.A rare karyotype,46,XX,-21,+t(21;21), was detected.This de nono chromosomal abnormality may be caused by the meiotic non-disjunction of chromosomes during gametogenesis along with the formation of Robertsonian translocation between homologous chromosome 21.     

Trisomy 21 by mirror duplication 46,XX,psu dic(21)ter rea (21q21q) (author's transl)

"Mirror image" duplication of chromosome 21 -- 46,XX,pter dic(21)ter rea(21q21q) -- was observed in a patient with the complete phenotype of trisomy 21 and a ses-sesquialtère de la SOD1.     

Ring chromosome 21 in the mother and 21/21 translocation in the fetus: karyotype: 45,XX,-21,-21,+t(21;21)(p11;q11)

In 1984 we reported a ring chromosome 21 in a normal woman with recurrent fetal wastage (Kleczkowska and Fryns, 1984). A 46,XY normal fetal karyotype was found after prenatal diagnosis at 14 1/2 weeks in a third pregnancy of this woman. In the present paper we report the prenatal diagnosis of a 21/21 translocation in a female fetus from her fourth pregnancy.     

Mosaicism for an additional partial chromosome 8: 46,XX/47,XX+der(8)(p21→qter)

Summary Report on mosaicism of an additional deleted chromosome 8 in a 12-year-old girl. She exhibits several typical but minor features of the trisomy-8 syndrome. Her IQ is 77 (Hawik).     

Polydactyly and Other Minor Stigmata Associated with 46,XX/47, XX,D+ Mosaicism

Mosaicism for normal and D-trisomic cells was found in a female child whose presenting abnormalities at birth were polydactyly of the left hand and foot, hemangiomata on the forehead and lumbosacral region, slightly peculiar facies and unusual dermal patterns. Her course during the first 27 months of life was characterized by normal growth, absence of clinical evidence of congenital heart disease, moderate developmental retardation, tonguetie and toe-walking. Trisomic cells were more numerous than normal cells in skin cultures, whereas the reverse was true for peripheral leukocytes.     

Doppelte aneuploidie: 46,XX/45,XO/47,XX,G+

Zusammenfassung Es wird über ein 7jähriges Mädchen berichtet, bei dem im Mosaik Zellen mit Trisomie 21, Monosomie X und normalem weiblichem Karyotyp gefunden wurden. Klinisch bot die Patientin das abgeschwächte Erscheinungsbild des Mongolismus. Die für das Turner-Syndrom typischen äußeren Veränderungen traten demgegenüber zurück.

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Summary A 7 year old girl is found to have a chromosome mosaic of trisomy 21, monosomy X, and normal female karyotype. The patient showed some clinical symptoms of mongolism, whereas Turner-stigmata were less obvious.

     

46,XX/46,XX,8p- mosaicism in a phenotypically normal female

A phenotypically normal female was found to have a chromosome 8 short arm deletion in a low percentage of the cells. The reduced proportion of monosomic cells in relationship with proband's age are discussed.     

Trisomy 13qter by tandem duplication 46, XX, dir dup 13 (q21 qter), 9qh+]

A tandem translocation of chromosome 13-46,XXdup13(q21 leads to qter)--occurred de novo in a patient with the following features: normal birthweight; early feeding difficulties; mild psychomotor retardation; low set hairline on the forehead; thick eyebrows; long, upturned eyelashes; pointed nose; micrognathia; large, flat, posteriorly rotated ears; multiple hemangiomata; normal hematological status. The hypothesis of an unequal crossing-over is discussed, as well as the possibility of constructing a phenotypic map of chromosome 13.     

Report of a case of true hermaphroditism with karyotype 45,X/46,XX/46,X,mar/47,XX,mar

The case of a 24-year-old man with hypoplastic external genitalia, lack of the right scrotal testis and gynaecomastia has been described. In the intermitotic cells the cytogenetic investigations revealed the presence of the X body and the absence of the Y body. A 45,X/46,XX/46,X,mar/47,XX,mar karyotype could be established. On laparotomy a rudimentary ovary, uterus and vagina were detected on the right side of the abdominal cavity.