Hae III restriction of DNA from three cases with nonfluorescent Y chromosomes (45XO/46XYnf)

Summary Hae III restriction patterns are reported in three cases with normal-sized but nonfluorescent Y chromosomes (XO/XYnf mosaics). The 3.4- and 2.1-kb fragment classes of reiterated Y chromosomal DNA were not present in the three cases. Mechanisms leading to these findings are discussed.     

Three cases of 45,X/46,XYnf mosaicism

Summary Three patients with 45,X/46,XYnf mosaicism were investigated by Southern hybridization using both X- and Y-specific DNa probes. Our patients seem to be hemizygous for the X chromosomal loci tested. Single-copy and low-copy repeated Y chromosomal sequences assigned to the short arm, centromere, and euchromatin of the long arm have been detected in our patients, suggesting the Y chromosomal origin of the marker chromosome both in male and female cases studied. Densitometry of autoradiographs revealed a double dose of Yp-specific fragments of the DXYS1 locus. None of the patients tested showed either the 3.4- or the 2.1-kb Hae III malespecific repeated DNa sequences. It seems likely that the Ynf is a pseudodicentric chromosome with duplication of Yp and euchromatic Yq sequences, the Yq heterochromatin being lost. Our findings indicate structural heterogeneity of the marker chromosome and in addition provide further information on the relative position of DNa sequences detectected by DNA probes 50f2, M1A, and pDP105.     

Ring Y chromosome: 45,X/46,X,r(Y) chromosome mosaicism in a phenotypically normal male with azoospermia

Summary Chromosome analysis of lymphocytes in a phenotypically normal male with azoospermia showed a mosaicism 45,X/46,X,r(Y). Seven other cases from the literature are discussed.     

True hermaphroditism in 45,X/46,XY mosaicism.

This report discusses the clinical findings on two patients with 45,X/46,XY mosaicism, two boys presented with penile hypospadias and cryptorchidism. A dysgenetic ovary and a testis were found in one boy, and a dysgenetic ovary in the other. Both patients can be considered to be true hermaphrodites on the basis of histology and clinical and hormonal observations. 45,X/46,XY mosaics have a wide range of phenotypic appearances and their gonadal morphology can also show great differences. However, the incidence of true hermaphroditism in individuals with 45,X/46,XY mosaicism is low and the reports in the literature rare. It is likely that males with 45,X/46,XY who suffer only mild maldevelopment of the external genitalia will not be recognized. In all patients with penoscrotal hypospadias and cryptorchidism with 45,X/46,XY mosaicism, the possibility of true hermaphroditism should be considered.     

Cell division and sister chromatid exchanges in 45,X/46,X,i(Xq) mosaicism

Summary The kinetics of cell division and sister chromatid exchanges were studied in PHA-stimulated short-term cultivations of peripheral blood by means of the BUDR/FPG technique in controls and in five patients with 45,X/46,X,i(Xq) mosaicism. No significant differences in the length of the cell cycle were observed between 45,X/46,X,i(Xq) and control 46,XX cells. The number of SCE on late i(Xq) was only nonsignificantly elevated (0.6 per i(Xq)) against the value expected on the basis of its relative length.     

A complex mosaicism 45,X/46,X,del(Xq)/46,X,idic(Xq) in a patient with secondary amenorrhea

A complex mosaicism involving the X chromosome was found in a 35-year-old female affected by secondary amenorrhea and short stature. Her karyotype was: 45,X[20]/46,X,del(X)(pter-->q26::qter)[15]/46,X,idic(X)(pter-->q26::q26-->pter)[9]. No cell contained both abnormal X chromosomes. This observation would suggest a possible mechanism underlying the formation of isodicentric chromosomes.     

Prenatal diagnosis of 45,X/46,XX mosaicism and 45,X: implications for postnatal outcome.

The prognosis for 45,X/46,XX mosaicism diagnosed prenatally has yet to be established. We report our experience with 12 patients in whom prenatal diagnosis of 45,X/46,XX mosaicism was detected by amniocentesis for advanced maternal age or decreased maternal serum alpha-feto protein and compared them with 41 45,X/46,XX patients diagnosed postnatally. The girls in the prenatal group range in age from 3 mo to 10 years. All have had normal linear growth. Four had structural anomalies including: ASD (n = 1); ptosis and esotropia (n = 1); labial fusion (n = 1); and urogenital sinus, dysplastic kidneys, and hydrometrocolpos (n = 1). Gonadotropins were measured in seven; one had elevated luteinizing hormone/FSH at 3 mo of age. One has developmental delay and seizures as well as ophthalmologic abnormalities. None would have warranted karyotyping for clinical suspicion of Turner syndrome. The prevalence of 45,X/46,XX mosaicism is 10-fold higher among amniocenteses than in series of postnatally diagnosed individuals with Turner syndrome, which suggests that most individuals with this karyotype escape detection and that an ascertainment bias exists toward those with clinically evident abnormalities. The phenomenon of a milder phenotype for the prenatal group is similar to that observed for 45,X/46,XY diagnosed prenatally. Prenatal counseling for 45,X/46,XX in the absence of such ultrasound abnormalities as hydrops fetalis should take into account the expectation of a milder phenotype (except, possibly, with respect to developmental delay) than that of patients ascertained postnatally. The same does not hold true for 45,x diagnosed prenatally.     

A case of true hermaphroditism with 45X/46XY mosaicism

Summary The authors describe a case of true hermaphroditism of mainly female phenotype, ambiguous external genitalia, and ovotestis. The cytogenetic studies revealed 45X/46XY mosaicism and an absence of Barr bodies.     

Dicentric Y chromosome in a male pseudohermaphrodite 45,X/46,X, dic (Y)/47, XYY]

The mosaicism 45,X/46,XY,terrea(Y,Y)(pterpter)/47,XYY was observed in an 8-month-old child with male pseudohermaphroditism. The presence of a 47,XYY population points to a post-zygotic origin of the rearrangement. The loss of Yp material is in favor of localization of masculinization factor(s) to the proximal segment of Yq. Twenty-two relevant observations reported in the literature previously are discussed.     

Ambiguous Genitalia in a Newborn with 45,X/46,X,Idic(Y) Ovotesticular Disorder of Sex Development

ObjectiveTo discuss a case of ovotesticular disorder of sex development (DSD) with ambiguous genitalia, isodicentric Y sex chromosome mosaicism, and unique histopathologic findings.MethodsWe report the clinical, laboratory, imaging, and operative findings, and we highlight the pertinent features of this case. Results of hormonal and genetic testing are reviewed, and histopathologic findings are illustrated.ResultsA term newborn had ambiguous genitalia and was found to have an uncommon 45,X/46,X,idic(Y) karyotype. This infant had a 2-cm phallic structure, a penoscrotal hypospadias, a gonad easily palpable in the right scrotum, and a second gonad palpable high in the left inguinal canal. On ultrasonography, both gonads appeared as normal testicles, and no müllerian structures were identified. Testosterone and dihydrotestosterone levels were normal for a male neonate. After assessment of the patient at 2 months of age because of an incarcerated left inguinal hernia, both gonads were removed and were found to have both testicular and ovarian tissues spread throughout, with a fallopian tube on the left and an incipient juvenile granulosa cell tumor on the right. He was then diagnosed with ovotesticular DSD and continued to be raised as a boy.ConclusionThis male infant had undervirilization and an ovotesticular DSD. He had evidence of both ovarian and testicular tissues, in conjunction with apparent alterations in local müllerian inhibiting substance levels that allowed one fallopian tube to be preserved. The proportion of actively transcribed Y material in the chromosomes of patients with this karyotype may partially explain the variable phenotypes that can occur. (Endocr Pract. 2009;15:732-736)     

Monozygotic twins with Turner's syndrome and mos 45,X/46,X,r,(Y)

A pair of monozygotic twins with Turner's syndrome was studied using combined cytogenetic techniques and a mos 45,X/46,X,r(Y) was demonstrated in both. One of the twins presented clitoral hypertrophy. Surgery was performed and uterus, bilateral Fallopian tubes, bilateral epididymis and bilateral streak gonads with a small nodule of testicular tissue containing numerous seminiferous tubules were found in both.     

45,X/46,X,dic(Yq) mosaicism and mixed gonadal dysgenesis. Case report and review of the literature.

A 4 year 7 month-old boy with ambiguous genitalia, histological evidence of mixed gonadal dysgenesis, and 45,X/46,X,dic(Yq) mosaicism is reported. The identity of the dicentric Y chromosome was stablished by its typical fluorescent banding patterns and the presence of two centromeres demonstrated by C-band technique. A review of the literature yielded nine additional cases of mosaic 45,X/46,X,dic(Yq). Phenotypical and histological findings among these cases were compared, and the possible localization of the genes responsible for testicle induction and maturation is discussed.     

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.