45,X/46,XYq dic-Geschlechtschromosomenmosaik

Zusammenfassung Es wird über eine Patientin mit Kleinwuchs, Adipositas und sexuellem Infantilismus berichtet. Die Abklärung ergab ein 45,X/46,XYq dic-Mosaik. Es folgt eine Zusammenfassung der bis jetzt in der Literatur beschriebenen Fälle von Ydic. Das klinische Bild unterscheidet sich nicht wesentlich von jenem des 45,X/46,XY-Mosaiks. Anschließend werden die Zusammenhänge zwischen strukturellen Aberrationen des Y-Chromosoms und Phänotypus diskutiert.

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45,X/46,XYq dic-Sexchromosome mosaic

Summary This is the report on an obese girl with small stature and sexual infantilism. A 45,X/46,XYq dic mosaic was found in blood and fibroblast cultures. A summary is given of the cases so far reported in the literature. The clinical picture does not differ significantly from that of 45,X/46,XY cases. The relationship of phenotype and structural abnormalities of the Y chromosome is discussed.

     

Karyotype 46,XY,22p+ in a male patient (author's transl)

The authors report the case of a 2-month-old infant with psychomotor retardation and several physical stigmata. Cytogenetic studies of the patient using the normal technique show in all the cells a karyotype 46,XY with a G group chromosome substituted by an F-like mediocentric element with satellites. The R, G and C-banding methods reveal that it is the 22 with too developed short arms (22p+). This element was found in the mother's and maternal grandfather's karyotypes although they both present normal phenotypes. The authors advance two hypotheses concerning the origin of the alteration but cannot exclude a possible connection between this particular chromosome and the proband's anomalies. The difficulties of genetic counselling in this case are evident.     

Karyotype study ofDurio zibethinus L

Durio zibethinus hasn=14 chromosomes with median, submedian and almost subterminal primary constrictions, and four chromosomes with secondary constrictions. On basis of the karyotype, the species may not be considered a primitive one, as suggested byCorner in his theory on the origin of modern trees.     

Ovaries and Female Phenotype in a Girl with 46,XY Karyotype and Mutations in the CBX2 Gene

A girl with a prenatal 46,XY karyotype was born with a completely normal female phenotype, including uterus and histologically normal ovaries. In mice with a similar phenotype, the ablation of M33, an ortholog of Drosophila Polycomb, causes male-to-female sex reversal. The analysis of the human homolog of M33, Chromobox homolog 2 (CBX2), in this girl revealed loss-of-function mutations that allowed us, by placing CBX2 upstream of SRY, to add an additional component to the still incomplete cascade of human sex development.     

46,XX/46,XX,r (2)(p25q37) mosaicism: clinical and cytogenetic studies.

A severely mentally retarded and physically handicapped girl is described who has 46,XX/46,XX,r(2)(p25q37) mosaicism. This is the first ring 2 chromosome to be described in Man. Studies of the behaviour of the ring showed that it was stable in diploid cells which had increased in frequency over a period of seven years, but unstable in tetraploid cells which were at a much higher frequency than in normal individuals. It is concluded that in some cases the phenotypic consequences of ring chromosome formation may be due more to their disturbing the regulation of cell division than to the loss of genetic material. Current models of ring chromosome behaviour do not account for the induction of tetraploidy.     

Mosaic 13 trisomy due to de novo 13/13 translocation with subsequent fission. Karyotype: 46,XX,-13, +t(13;13)(p11;q11)/46,XX,del(13)(p11). A second example

In this paper we report a second example of 13 trisomy mosaicism due to de novo 13/13 translocation followed by postzygotic fission of the translocation chromosome in a polymalformed female newborn.     

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.     

Human cytogenetics: 46 chromosomes, 46 years and counting

Human cytogenetics was born in 1956 with the fundamental, but empowering, discovery that normal human cells contain 46 chromosomes. Since then, this field and our understanding of the link between chromosomal defects and disease have grown in spurts that have been fuelled by advances in cytogenetic technology. As a mature enterprise, cytogenetics now informs human genomics, disease and cancer genetics, chromosome evolution and the relationship of nuclear structure to function.     

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.

     

福建大头蛙的核型及带型分析

利用骨髓细胞蒸气固定法制备染色体标本,研究了福建大头蛙(Limnonectesfujianensis)黄山居群的核型、C 带和Ag NORs。结果表明,福建大头蛙核型为2n =2 2 =2 0M 2SM ,NF =44,次缢痕位于No 1 0q ;各染色体均有着丝粒C 带,3p、9q出现插入型C 带;Ag NORs位于1 0q。