Fusion of the short arms of one X chromosome in a patient with gonadal dysgenesis

Summary The origin of an abnormal large X chromosome in a patient with gonadal dysgenesis is interpreted as a fusion of the short arms of one X during the first division of the zygote.     

Dicentric Yp chromosome in a patient with the gonadal dysgenesis and gonadoblastoma.

A patient with a short stature, gonadal dysgenesis, and bilateral gonadoblastoma had 3 cell lines in the blood and in the skin: 46,X,dic (Y) (pter vector q 1 2 : : 1 2 vector pter) as a major cell line 46,X,del(Y) (q 1 2), and 45,X. The intensively flourescent distal part of the Yq was deleted in both the Y-dicentric and Yq--chromosome. Both parents had normal karyotypes.     

De novo duplication xq22-q23 in a girl with short stature and gonadal dysgenesis

A female of 20 years of age with short stature, gonadal dysgenesis and Turner stigmata with a de novo dup Xq22-q23 was studied. The maternal cytogenetic study was normal. This case represents the smallest Xq duplication in an abnormal female. We discuss the possibility of a maternal imprinting.     

Exclusively paternal X chromosomes in a girl with short stature

A 13 1/2 year-old girl with short stature and very few Turner stigmata revealed 45,X/46,XX mosaicism with 90%–100% 46,XX cells in three sequential blood lymphocyte cultures. Molecular investigation of the parental origin of her X chromosomes revealed homozygosity for paternal X markers and an absence of maternal markers. Luteinizing hormone response to growth hormone releasing hormone was increased. Impaired gonadal function and shortness of stature in this case could be a result of the mild mosaicism with a 45,X cell line and/or is a consequence of the paternal-only origin of her X chromosomes.     

X-X translocation in a patient with gonadal dysgenesis and the problem of phenotype-karyotype correlations

Summary A sex-chromatin-positive woman without stunted growth, but with primary amenorrhea, and some stigmas of pure gonadal dysgenesis had the chromosome constitution 45,X/46,Xt(X;X)(q27;q27). The abnormal chromosome formed a large Barr body and was late-labeling. The chromosome consisted of two X chromosomes attached by their long arms (end-to-end), both apparently having the partial distal deletion. Both centromeric regions showed C-staining but only one constriction. The chromosome is interpreted as an isodicentric with only one centromere functioning. Some problems of phenotype-karyotype correlations are discussed.     

Monosomy X and gonadal dysgenesis in a buffalo heifer (Bubalus bubalis)

Investigations on a 3-yr-old river buffalo heifer presenting anestrus revealed a chromosome make-up of 2n=49 in the lymphocyte cultures, compared with the 2n=50 characteristic of riverine buffalo. The missing chromosome was identified as one of the Xs by karyotypic analysis, and monosomy X was confirmed by C and G-banding techniques. Both ovaries of the heifer were underdeveloped, although the other components of the internal genitalia were normal. The phenotypic and karyotypic features confirmed this to be a case of ovarian dysgenesis with 49,XO karyotype similar to that of the Turner's syndrome in man and other mammals.     

Cytogenetic and clinical findings in mares with gonadal dysgenesis.

Gonadal dysgenesis in the mare is associated with several different karyotypes, including sex chromosome aneuploidy (63,X; 63,X/64,XX; 63,X/64,XY or 65,XXX), the normal male complement (64,XY) and autosomal deletion (64,XX?del2q-). The 63,X is the most common karyotype found in gonadal dysgenesis. Aneuploid cases probably represent spontaneous chromosome non-disjunction during oogenesis, spermatogenesis or early embryonic development. Cases with XY or autosomal deletion may be inherited defects or of spontaneous origin.     

Partial deletion of the X chromosome in gonadal dysgenesis 46,X,del(X)(p22) identified by BUdR treatment

Summary In this report we describe a deletion of the short arm of the X chromosome in a 16-year-old female with gonadal dysgenesis.The breakpoint was localized by BUdR treatment and acridine orange staining in region 2, band 2.Of the examined cells, 3% showed an early replication of the deleted X chromosome.     

An unusual dicentric Y chromosome with a functional centromere with no detectable alpha-satellite

We describe an unusual marker chromosome Y. This marker is present in 5% of the lymphocytes of a dysgenetic woman showing a mosaic karyotype 45,X/46,XY/ 47,XY+mar. Q-banding revealed that the marker was morphologically identical to the Y chromosome of the patient but presented the primary constriction in the heterochromatic region. C-banding confirmed that the heterochromatic region was C-positive; furthermore, it showed two spots in the euchromatic region in a position corresponding to that of the centromere in the normal Y Fluorescence in situ hybridization with the centromere-specific probe pDP 97 and the pancentromeric alpha-satellite probe 2730 failed to detect any signal at the primary constriction site. To improve the characterization of the marker chromosome, hybridization was performed using pDP 105, a probe located on the short arm of the Y chromosome, together with chromosome-Y- specific paint-hybridizing to the single sequence spanning the Y short arm. In both cases, positive signals telomeric to the inactive centromere were observed. Possible mechanisms resulting in the formation of the marker chromosome are discussed.     

Management of males with 45,X/46,XY gonadal dysgenesis

Males with the 45,X/46,XY karyotype and malformations of the external genitalia carry an increased risk of developing germ cell neoplasia of the gonads. We have studied gonadal tissue from 10 individuals, 0.3-17 years of age, with a male phenotype and either hypospadias and/or cryptorchidism. Four patients, 0.3-15 years of age, had carcinoma in situ, 1 boy had Sertoli-cell-only pattern and the remainder prepubertal histology. Gonadoblastoma or invasive carcinoma was not found. On the basis of our current knowledge we propose a strategy for management and follow-up of these boys in order to detect possible premalignant histological changes early and prevent development of a gonadal tumour.     

XY gonadal dysgenesis in a Charolais heifer

The anatomical and cytogenetical findings on a three quarter Charolais heifer which failed to show oestrus are described. The heifer had a karyotype of 60, XY in all tissues studied and was sex chromatin negative. The vulva and vagina were normal, the cervix had a double external os, the left ovary was partially hypoplastic, there was no right gonad and a cystic dilatation of the fallopian tube was recorded.     

A male pseudohermaphrodite with a dicentric Y chromosome

Summary A 13-year-old male pseudohermaphrodite (mixed gonadal dysgenesis, unilateral testicular differentiation) was found to be a chromosomal mosaic of the 45, XO/46, XY type, the Y chromosome being a symmetrical dicentric chromosome. Presumed Y chromosomes similar to this one have been observed before, but their identification was not supported by autoradiographic data. In the present study the identification of the dicentric as a Y chromosome was supported by observing a relatively late DNA replication during the S period. The differentiation of testicular tissue on one side may be related to the presence of short arm material of the Y chromosome in the genome of the XY dic cells.This study was supported by a Research Grant from the National Institute of Child Health and Human Development (1RO1-HD0999-03) and by a Public Health Service Training Grant in Pediatric Endocrinology and Metabolic Diseases (2T1-AM-5190).     

Hemophilia A in a female with gonadal dysgenesis and XX karyotype

The authors present a case of a coincidence of two very rare diseases in a female--hemophilia A and gonadal dysgenesis; both may be caused by chromosomal and genetic abnormalities. The girl, aged 22, presented severe hemophilia with excessive haematoma after bruising and recurrent hemarthroses, had undeveloped breasts and very hypoplastic internal genital organs. Laboratory tests revealed factor VIII: C - 1%, VIII R: AG - 160%, VIII:WF - 111%, 46, XX karyotype, elevated LH in urine - 25 IU/l. This coincidence had a beneficial effect since there was no menorrhagia.