1/308. True hermaphroditism associated with microphthalmia.A 4-year-old boy with an undescending left testis, penoscrotal hypospadia and bilateral microphthalmia was admitted to our hospital. Chromosome analysis revealed a karyotype of 46, XX del(x)(p2 2,31) and the sex-determining region of the y chromosome (SRY) was negative. The right testis was located in the scrotum and a left cystic ovary-like gonad, a salpinx and a unicorn uterus were found in the left inguinal canal. Histologically the gonad was an ovotestis in which primordial follicles covered infantile seminiferous tubules. Microphthalmia is observed in some congenital syndromes caused by interstitial deletion of the X chromosome. This case suggested that the short arm of the X chromosome was involved in the differentiation of the gonad. Very closely located follicles and infantile seminiferous tubules indicated that induction of meiosis in the fetus was controlled by the local microenvironment in follicles and seminiferous tubules, and not by the systemic hormonal condition.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
2/308. 'Identical' twins with discordant karyotypes.A chromosomal abnormality in one of the fetuses of a monozygotic twin pregnancy is a rare phenomenon. In the prenatal unit of our cytogenetics laboratory we have recently come across two such heterokaryotypic twin pregnancies. In both cases ultrasound abnormalities were detected in one fetus of each twin pair. Chromosomal analysis showed that one twin pregnancy was discordant for trisomy 21 and the other for 45,X. Ultrasonographic examination suggested a monochorionic twin pregnancy in each case and dna studies confirmed that both sets of twins were monozygotic. Both pregnancies were terminated. Biopsies taken from different sites of the placentas showed chromosomal mosaicism in both cases. There was no clear correlation between the karyotype found close to the site of the umbilical cord insertion in the placenta and the karyotype of the fetus. Sampling of amniotic fluid from both sacs is recommended in diamniotic twin pregnancies if one (or both) of the fetuses has ultrasound abnormalities, even if the twins are apparently monochorionic.- - - - - - - - - - ranking = 6keywords = karyotype (Clic here for more details about this article) |
3/308. Risk of gonadoblastoma in female patients with y chromosome abnormalities and dysgenetic gonads.We report two female patients with gonadal dysgenesis and sex chromosome mosaicism involving the y chromosome. Conventional karyotyping was supplemented with fluorescent in situ hybridisation techniques in order to confirm the presence of Y chromosomes. One patient is a phenotypic female with karyotype 45,X/46,X,idic(Y)(q11.2). She underwent a laparoscopic gonadectomy at which streak ovaries without evidence of gonadoblastoma were removed. The second patient presented as a virilised female with karyotype 45,X/47,XYY. At laparoscopy, she was found to have mixed gonadal dysgenesis with a gonadoblastoma in situ. We recommend early gonadectomy in female children presenting with gonadal dysgenesis and the presence of a y chromosome although once the gonadoblastoma locus on y chromosome gene has been cloned it may be possible to identify those patients who have a low risk of developing gonadoblastoma.- - - - - - - - - - ranking = 2keywords = karyotype (Clic here for more details about this article) |
4/308. 45,X/46,X,r(Y) karyotype transmitted by father to son after intracytoplasmic sperm injection for oligospermia. A case report.BACKGROUND: The advent of assisted reproductive techniques, such as intracytoplasmic sperm injection (ICSI), has permitted conception and successful pregnancy for an increasing population of infertile men. Approximately 13.7% of infertile men with aspermia and 4.6% with oligospermia have a coexistent chromosome abnormality. Although the ICSI procedure appears safe thus far, early studies are in progress to evaluate outcomes of such pregnancies. For men whose infertility is linked to genetic conditions, it is an unprecedented challenge to predict the potential effects on their offspring. CASE: At 18 weeks' gestation, a 45,X/46,X,r(Y) karyotype was found on genetic amniocentesis performed for advanced maternal age. The pregnancy was achieved by ICSI using sperm from the husband, who was infertile due to severe oligospermia. Subsequently the same karyotype was found in the father. To our knowledge, this is the first reported case of familial transmission of ring y chromosome. CONCLUSION: It is strongly recommended that ICSI and other new assisted reproductive techniques be preceded by genetic screening for male infertility as well as other indications warranted by the family history since traditional risk assessment may require revision and outcomes may be uncertain in some cases.- - - - - - - - - - ranking = 6keywords = karyotype (Clic here for more details about this article) |
5/308. Complete androgen insensitivity in a 47,XXY patient with uniparental disomy for the X chromosome.We describe a unique patient with complete androgen insensitivity syndrome and a 47,XXY karyotype. Androgen receptor assay using cultured pubic skin fibroblasts showed no androgen-binding capacity. sequence analysis of the androgen receptor gene demonstrated two nonsense mutations, one in exon D and one in exon E. Microsatellite marker analysis showed that the patient is homozygous for all five Xq loci examined. The results suggest that the long-arms of the two X chromosomes are identical, i.e., uniparental isodisomy at least for Xq, and carry the same mutations in the androgen receptor gene. This explains how complete androgen insensitivity syndrome occurred in this 47,XXY individual.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
6/308. Prenatal ultrasound detection of a congenital epulis in a triple X female fetus: a case report.A case of congenital epulis in a triple X infant, whose intra-oral mass was first detected on a 33-week prenatal ultrasound, is described. Two previous ultrasound studies performed at 21 and 28 weeks' gestation showed normal facial anatomy, suggesting accelerated tumour growth during the third trimester. Genetic amniocentesis also showed the infant to possess a 47, XXX karyotype.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
7/308. Pentasomy X and hyper IgE syndrome: co-existence of two distinct genetic disorders.We describe a 10-year-old girl with features of a penta-X syndrome. cytogenetic analysis revealed a 49,XXXXX karyotype and molecular analysis of X-linked polymorphic markers showed that this aneuploidy arose by successive maternal non disjunctions. Apart from these features the patient has a lifelong history of eczema, recurrent pneumonia, and staphylococcal abscesses. Together with consistently increased serum IgE levels, low antibody responses, and low levels of serum IgA and IgG2, these findings are characteristic for the hyper IgE syndrome. While pentasomy X may be due to sequential non disjunctions in meiosis I and meiosis II in the mother, the underlying pathomechanism in hyper IgE syndrome remains unclear. This case is the first with co-existence of pentasomy X and hyper IgE syndromes.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
8/308. Short stature in a 46,XX male adolescent.We describe a patient with a 46,XX karyotype who was assessed because of short stature and a subnormal rate of linear growth. The patient had normal male external genitalia. Endocrinologic analysis revealed elevated levels of luteinizing hormone and follicle-stimulating hormone but an exaggerated gonadotropin response to luteinizing hormone-releasing hormone stimulation. The growth hormone response to insulin-induced hypoglycemia was also exaggerated. All sequences examined on the sex-determining region Y gene were present. The diagnosis was 46,XX male with the major manifestation of short stature.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
9/308. frasier syndrome: a cause of focal segmental glomerulosclerosis in a 46,XX female.The description of frasier syndrome until now has been restricted to XY females with gonadal dysgenesis, progressive glomerulopathy, and a significant risk of gonadoblastoma. Mutations in the donor splice site in intron 9 of the Wilms' tumor (WT1) gene have been shown to cause frasier syndrome and are distinct from WT1 exon mutations associated with denys-drash syndrome. The WT1 gene, which is essential for normal kidney and gonadal development, encodes a zinc finger transcription factor. The intron 9 alternative splice donor site mutation seen in frasier syndrome leads to loss of three amino acids ( KTS isoform), thus disrupting the normal ratio of the KTS/-KTS isoforms critical for proper gonadal and renal development. This study examines two sisters with identical intron 9 mutations. The proband carries a classic diagnosis of frasier syndrome with 46,XY gonadal dysgenesis, whereas her sister has progressive glomerulopathy but a 46,XX karyotype and normal female development. This indicates that the proper WT1 isoform ratio is critical for renal and testicular development, but apparently does not affect either ovarian development or function. It is proposed that the clinical definition of frasier syndrome should be broadened to include 46,XX females with normal genital development and focal segmental glomerulosclerosis associated with a WT1 intron 9 donor splice site mutation. Nephrologists need to consider the possibility of this heritable syndrome in evaluation of females with focal segmental glomerulosclerosis and to consider their risk for gonadal malignancy, as well as the risk for kidney disease, gonadal dysgenesis, and malignancy in their offspring.- - - - - - - - - - ranking = 1keywords = karyotype (Clic here for more details about this article) |
10/308. Sex reversal due to Xp disomy by t(X;Y)(p21;q11).A 20-month-old infant exhibiting psychomotor retardation, dysmorphisms and ambiguous external genitalia was found to have a 46-chromosome karyotype including a normal X chromosome and a marker Y with most of Yq being replaced by an extra Xp21-->pter segment. The paternal karyotype (G and C bands) was 46,XY. The marker Y composition was verified by means of FISH with a chromosome X painting, an alphoid repeat and a DMD probe. Thus, the final diagnosis was 46,X,der(Y)t(X;Y)(p21;q11)de novo.ish der(Y)(wcpX ,DYZ3 ,DMD ). The patient's phenotype is consistent with the spectrum documented in 13 patients with similar Xp duplications in whom sex reversal with female or ambiguous genitalia has occurred in spite of an intact Yp or SRY gene. A review of t(X;Y) identifies five distinct exchanges described two or more times: t(X;Y)(p21;q11), t(X;Y)(p22;p11), t(X;Y)(p22;q11-12), t(X;Y) (q22;q12), and t(X;Y)(q28;q12). These translocations probably result from a recombination secondary to dna homologies within misaligned sex chromosomes in the paternal germline with the derivatives segregating at anaphase I.- - - - - - - - - - ranking = 2keywords = karyotype (Clic here for more details about this article) |
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