Triple mosaicism 45,XY,--18/46, XY/47,XY,+18.

A patient with symptoms clinically resembling Edwards's syndrome is presented. Cranial asymmetry, thoracic and lumbar hemivertebrae, and an additional rib were the unusual features. The cytogenetic studies revealed the coexistence of three separate cell lines with 45,XY,--18/46,XY/47,XY,+18 complement.     

Features of trisomy 18 and 18p-syndromes in an infant with 46, XY, i(18q)

An isochromosome for the long arm of chromosome number 18 - 46,XY,i(18q) - was found in an infant who had features of both trisomy 18 and 18p- syndromes. Findings compatible with trisomy 18 included postmature delivery, prominent occiput, severe congenital heart disease, overlapping fingers, and rocker-bottom feet. Those of 18p- syndrome, which frequently resembles Turner syndrome, were downward obliquity to the palpebral fissures, short, webbed neck, low posterior hairline, and widely-spaced nipples. The infant died of heart failure at 3.5 months of age. Parental karyotypes were normal.     

Trisomy 18 and 18p- features in a case of isochromosome 18q [46,XY,i(18q)]: prenatal diagnosis and autopsy report

This paper reports the prenatal diagnosis and autopsy findings of a case of true isochromosome 18q [46,XY,i(18q)] with severe cephalic malformations. Comparison is made with other cases of i(18q).     

Novel isodicentric chromosome 18 in an abnormal infant with a mosaic karyotype [46,XY/46,XY,-18,+dic(18)(q12.2])

A previously unreported isodicentric chromosome 18 was discovered in an abnormal infant boy whose mosaic karyotype was 46,XY/46,XY,-18,+idic(18)(q12.2). His constellation of congenital anomalies was typical of the 18q-syndrome. The clinical and cytogenetic characteristics of this patient are reported, and the literature concerning isochromosomes of 18 is reviewed.     

Double heteroploidy, 46, XY, t(13q14q), +18, in a spontaneous abortus

Karyotype analysis of a spontaneous abortus revealed a double heteroploidy, 46, XY, t(DqDq), + 17- 18. The application of trypsin banding technique resulted in the identification of the karyotype as 46, XY, t(13q14q),+18. Peripheral lymphocyte culture from the mother of the abortus revealed an achromatic constriction in the long arm of a chromosome 16 in 6.6 percent of the analysed cells.     

染色体46,XY,t(18;21)(q11;q22)平衡易位携带者一例

目的报道染色体46,XY,t(18;21)(q11;q22)平衡易位携带者1例。方法采用外周血淋巴细胞培养法,G显带。结果染色体核型分析为46,XY,t(18;21)(q11;q22)。结论平衡易位是导致不良孕产的重要原因,也是导致男性不育的常见原因。如查出平衡易位携带者,给予他们正确的优生指导及产前诊断,对降低出生缺陷的发病率有重要的作用。     

Origin of 46,XY/46,XY,r(19) mosaicism

We report on a case of 46,XY/46,XY,r(19) mosaicism. The patient shows minimal clinical abnormality and the terminal deletions prerequisite for the ring formation are not microscopically discernible. The origin of the mosaicism is discussed. Firstly, the mosaicism may represent chimerism with a prezygotic origin of the ring chromosome; secondly, the ring chromosome could have arisen postzygotically; and thirdly, the ring could have been of a prezygotic origin with the apparently normal cells actually containing reopened rings. The consequences of these hypothesis on genetic counselling are discussed.     

Trisomy 18q: 46, XX,13q+,t(13;18)(q32;q11) in a newborn associated with multiple congenital anomalies due to paternal reciprocal translocation, 46, XY,-13,+der(13)/t(13;18)(q32;q11)

A 20-day-old female neonate presented with multiple congenital anomalies, convulsions and failure to thrive. Karyotype analysis of the proposita revealed an unbalanced translocation, 46, XX,13q+,t(13;18)(q32;qll)pat resulting in partial trisomy 18q. Her father and a 5-year-old sister were phenotypically normal, balanced translocation carriers, 46, XY, -13, + der(13),t(13;18)(q32;qll) and 46, XX,-13,+der(13),t(13;18)(q32;qll), respectively. The case presented here is the second liveborn reported with trisomy 18q and is of interest from the point of view of the structural chromosomal aberration resulting in the manifestations of most features of trisomy 18 and some of 13q monosomy. The infant died due to convulsions at the age of 2 months.     

46,XY/46,XY,21q- mosaicism in an infant with neutropenia and properdin deficiency.

An infant with neutropenia, properdin deficiency, and a 46,XY/46,XY,21q- mosaicism is described. It is not known whether these two findings are related to the missing 21q material. The propositus is normal in appearance, and has none of the phenotypic features associated with the G-group deletion syndromes.     

Phenotypic spectrum of 45,X/46,XY individuals

We report on five patients with 45,X/46,XY mosaicism. In these subjects, as well as in 58 individuals from the literature with a similar chromosome constitution, we did not find a preponderance of 46,XY cells among patients showing ambiguous to abnormal male external genitalia when compared to those patients with slight or no virilization. However, the average frequency of 46,XY cells in blood in these mosaic individuals suggests that this sample includes mainly individuals whose mosaicism originated early in embryonic cell division. Those individuals whose mosaicism originated later are not significantly represented in this sample and would have higher frequencies of 46,XY cells. These individuals would be excluded from an intersex sample if they had well-virilized genitalia. This ascertainment bias suggests that the degree of virilization depends on the frequency of 46,XY cells.     

Fluorescence in-situ hybridization analysis of chromosomal constitution in spermatozoa from a mosaic 47,XYY/46,XY male

Sex-chromosome mosaicism in spermatozoa from a mosaic 47,XYY[20%]/46, XY[80%] male with fertility problems was assessed using triple-probe fluorescence in-situ hybridization (FISH) studies. Chromosome-specific probes for X, Y and 18 were used, and the possible outcomes were deduced. In normal haploid spermatozoa of the patient and a normal 46,XY male control, the X:Y ratio was close to 1:1. There was a significant difference in the total incidence of karyotypically abnormal spermatozoa between the patient and the 46, XY male control (2.31% versus 1.46%, P < 0.0001). The incidence of some types of disomic spermatozoa X+Y+18 (24,XY) and X+18+18 (24,X, +18), or diploid X+Y+18+18 (46,XY) spermatozoa was significantly increased in the patient's semen sample. There was, however, no significant difference in the incidence of disomic Y+Y+18 (24,YY) spermatozoa. Because the majority of the patient's spermatozoa was karyotypically normal, the aetiology of his fertility problems was unclear. These results add to the growing body of information regarding chromosome abnormalities in spermatozoa from men who are mosaic for sex chromosome abnormalities. In these men, FISH analysis of spermatozoa may be warranted to determine the relative percentages of abnormal cells, and to determine if in-vitro fertilization with preimplantation genetic diagnosis may increase the likelihood of a successful pregnancy.     

Prenatal diagnosis of 46,XY/46,XX mosaicism: a case report

We report on the prenatal diagnosis of a fetus with 46,XY and 46,XX cell lines with a normal male phenotype. Cytogenetic and molecular studies ruled out the possibility of maternal cell contamination and showed that all the X chromosomes present in both fetal cell lines were derived from a single maternal X chromosome. This suggests 46,XY/46,XX mosaicism.     

A true hermaphrodite dispermic chimera with 46, XX and 46, XY karyotypes

A 16-year-old male with hypospadias and gynaecomastia had a rudimentary uterus with a right Fallopian tube and ovary; the left gonad was a functioning testis. Cytogenetic studies showed cells with 46 , XX and 46 , XY sex chromosomes in cultured blood, skin and gonadal tissues. Cells with the 46 , XX constitution predominated in all tissues. Extensive investigations failed to demonstrate blood cell and serum chimerism, but there was little genetic variation of these characters between family members. Cytogenetic studies demonstrated that the father had contributed different marker chromosomes to the 46 , XY and 46 , XX cell lines of the propositus, whereas the mother had contributed the same two informative markers to both cell lines. The patient was a chimera with two diploid cell lines of different sex that had developed from the products of two separate acts of syn-gamy. Dispermy was demonstrated, and, whereas there was no evidence of different maternal contributions to the chimeric cell lines, uncertainty remains that these were identical.     

46,XY pure gonadal dysgenesis with non-fluorescent Y chromosome

A 46,XY karyotype with a non-fluorescent Y chromosome was found in an infantile girl aged 16 with primary amenorrhea. Identification of the Y chromosome was made by different staining techniques and a photometric scanning method. The histology of the streak gonad also indicated the Y character of the chromosome. The authors' interpretation is a 46,XY pure gonadal dysgenesis with a non-fluorescent Y chromosome.     

H-Y antigen in 46,XY pure testicular dysgenesis

Clinical, cytogenetic, pathologic and histocompatibility-Y (H-Y) antigen studies were performed on a phenotypic female with primary amenorrhea and streak gonads. Pathological examination of tissues removed at total hysterectomy and bilateral salpingo-gonadectomy showed gonadoblastoma and dysgerminoma of left streak. A single F-body (Y chromosome) was found in buccal smears. Analysis of blood cells and tumor fibroblasts showed a 46, XY chromosome constitution (Q-banding). The data were consistent with a diagnosis of 46, XY pure testicular dysgenesis. Positive results for H-Y antigen were found in this case.     

Two successful pregnancies in a 46,XY patient

Two successful pregnancies (singleton followed by twins) following ovum donation/in-vitro fertilization in a 46,XY woman have been studied. Although similar cases have previously been presented: in a pure XY patient and in a 45,X/46,XY patient, this case is one in which a subsequent successful pregnancy has resulted. In such patients, the rate of Caesarean section appears to be increased, and we postulate that the hypoplastic nature of the uterus, although able to respond quite well to both exogenous and endogenous hormones to accept and maintain a pregnancy, may lack the capability to respond fully in labour by dilating appropriately.      

Body size and shape in 46,XY females with complete testicular feminization

Twenty-five anthropometric measurements were recorded from eight adult 46,XY females with complete testicular feminization and they were compared with those of female relatives of the patients and control females. In most dimensions 46,XY females were larger than normal females, the difference being close to one SD unit. The mean height of 46,XY females was 171.5 cm. The body proportions of 46,XY females were similar to those of normal females though, according to the results of analysis of covariance where the effect of size was controlled, there may be a tendency to slimmer body. The present findings suggest the presence of genes on the Y chromosome with a general size-increasing effect. They also indicate that the Y chromosome has an influence on the quantitative sex difference in body size. These conclusions are in accordance with the results of earlier studies which have indicated Y-chromosomal influence on stature and tooth size.     

H-Y antigen in 46,XY pure testicular dysgenesis.

Clinical, cytogenetic, pathologic, and histocompatibility-Y (H-Y) antigen studies were performed on a phenotype female with primary amenorrhea and streak gonads. Pathological examination of tissues removed at total hysterectomy and bilateral salpinog-gonadectomy showed gonadoblastoma and dysgerminoma of left streak. A single F-body (Y chromosome) was found in buccal smears. Analysis of blood cells and tumor fibroblasts showed a 46,XY chromosome constitution (Q-banding). The data were consistent with a diagnosis of 46,XY pure testicular dysgenesis. Positive results for H-Y antigen were found in this case.     

45,X/46,XY Mosaicism. Contrast of prenatal and postnatal diagnosis

The process of prenatal diagnosis is unique in that the diagnosis and prognosis are made without seeing the patient. 45,X/46,XY mosaicism presents a special problem in this regard. The phenotype of 45,X/46,XY postnatally diagnosed children (pediatric group) was compared to that of 6 fetuses who were diagnosed from 7,000 amniocenteses (prenatal group). These amniocenteses were performed primarily because of an increased risk of chromosome abnormality. The pediatric group (age birth—18 yr) were all phenotypically abnormal, although none were mentally retarded. Seven patients presented with ambiguous genitalia, while 2 had primary amenorrhea. Sexual assignment was changed in 2. Abnormalities included rudimentary phallus, urogenital sinus, hypospadias, undescended testes, and short stature. All 9 patients required at least one surgical procedure. In contrast, the prenatally diagnosed fetuses (ages 3 months to 31/2 yr) were all phenotypically normal males. Four were noted to have male genitalia on ultrasonography. Thus, the phenotype of 45,X/46,XY mosaicism in prenatally diagnosed fetuses can be markedly different from that of individuals diagnosed postnatally. This must be considered when counseling patients.     

Maternal translocation t(13:18)(q34:q11) and Edwar''s syndrome in a fetus: 47, XY, t(13:18)(q34:q11) + 18

A 32-year-old woman, who presented with four spontaneous abortions, was found to have a balanced translocation: 46,XX,t(13:18)(q34:q11). In the last pregnancy an amniocentesis was done. Abnormal constitution of the fetus had been detected: 47,XY,t(13:18)(q34:q11) + 18, and an abortion was induced. Examination of the fetal tissue confirmed the finding. The fetus showed the characteristics of Edward's syndrome. Through the patient's pedigree it was discovered that balanced translocation appeared in three generations.