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Background: Girls with Turner syndrome (TS) have a high incidence of primary ovarian insufficiency. Recent data show rates of spontaneous thelarche (ST) of 38% and spontaneous menarche (SM) of 15-16%, with higher rates in those with mosaicism., Summary: We systematically reviewed the literature for evidence regarding rates of ST and SM in TS and evaluated rates based on the type of chromosomal mosaicism. We searched MEDLINE via PubMed, Embase, and the Cochrane Database of Controlled Trials. Reference lists were screened. Studies reporting outcomes of ST and SM in girls with TS, diagnosed by genetic analysis, were included. Data was collected regarding study design, cohort type, cohort age, the number of participants with ST and SM, the individual age at diagnosis of ST and SM, the mean age of patients with ST and SM, sample size, the number of participants with secondary amenorrhea, and karyotype. Key Messages: In total 2,699 patients were assessed for ST and 2,890 for SM from 43 articles. Overall the rates of ST were 32% (95% CI 26.4-38.9) and SM 20.8% (95% CI 19.3-22.4). Girls with X monosomy had the lowest rates of ST (i.e., 13%; 95% CI 8.7-19.7) and SM (i.e., 9.1%; 95% CI 7.3-11.3). Girls with 45,X/47,XXX had the highest rates of ST (i.e., 88.1%; 95% CI 62-97.1) and SM (i.e., 66.2%; 95% CI 49.3-79.6)., Conclusions: Rates of ST and SM differ by karyotype in TS. When counseling patients, the karyotype should strongly influence discussions regarding pubertal development and the future reproductive potential., (© 2020 S. Karger AG, Basel.)

Background/aims: Splicing CYP19 gene variants causing aromatase deficiency in 46,XX disorder of sexual development (DSD) patients have been reported in a few cases. A misbalance between normal and aberrant splicing variants was proposed to explain spontaneous pubertal breast development but an incomplete sex maturation progress. The aim of this study was to functionally characterize a novel CYP19A1 intronic homozygote mutation (IVS9+5G>A) in a 46,XX DSD girl presenting spontaneous breast development and primary amenorrhea, and to evaluate similar splicing variant expression in normal steroidogenic tissues., Methods: Genomic DNA analysis, splicing prediction programs, splicing assays, and in vitro protein expression and enzyme activity analyses were carried out. CYP19A1 mRNA expression in human steroidogenic tissues was also studied., Results: A novel IVS9+5G>A homozygote mutation was found. In silico analysis predicts the disappearance of the splicing donor site in intron 9, confirmed by patient peripheral leukocyte cP450arom and in vitro studies. Protein analysis showed a shorter and inactive protein. The intron 9 transcript variant was also found in human steroidogenic tissues., Conclusions: The mutation IVS9+5G>A generates a splicing variant that includes intron 9 which is also present in normal human steroidogenic tissues, suggesting that a misbalance between normal and aberrant splicing variants might occur in target tissues, explaining the clinical phenotype in the affected patient., (© 2015 S. Karger AG, Basel.)

Women harbouring inactivating mutations in luteinizing hormone (LH) beta subunit (LHB) or LH receptor (LHCGR) genes have similar clinical manifestations characterized by female external genitalia, spontaneous breast and pubic hair development at puberty, and normal or late menarche followed by oligo-amenorrhea and infertility. Oestradiol and progesterone levels are normal for the early to midfollicular phase, but do not reach ovulatory or luteal phase levels, confirming lack of ovulation. Notably, serum LH levels are low in patients with LHB mutations and high in those with LHCGR mutations, whereas follicle-stimulating hormone levels are normal or only slightly increased. Pelvic ultrasound has demonstrated a small or normal uterus and normal or enlarged ovaries with cysts. Women with LHB mutations may be treated with hCG (human chorionic gonadotropin) or LH, whereas those with mutations in LHCGR are resistant. Lhb and Lhcgr knockout female mice are close phenocopies of the respective human mutations, and confirm that early follicular development, low levels of oestrogen production and theca cell development are independent of LH action, which is necessary for ovulation. Although inactivating mutations in LHB and LHCGR are rare in comparison to other genetic and non-genetic causes of hypogonadism, they should be considered in the differential diagnosis of oligo-amenorrhea and infertility., (Copyright 2009 S. Karger AG, Basel.)

Objective: The LH response of pituitary gland to gonadotropin-releasing hormone (GnRH) stimulation is not well defined in patients with mutant beta-subunit (Trp(8) to Arg(8) and Ile(15) to Thr(15)). Here we compared the relative activities and dynamics of LH secretion in patients with wild-type and variant LH following injection of GnRH., Methods: A GnRH stimulation test was performed in 33 patients with ovulatory disorders (patient group) and 29 women with normal ovulatory cycles (control group) heterozygous for the variant LHbeta allele. Blood samples were obtained up to 120 min after GnRH injection. Serum LH response was determined by comparing the results of LH immunoassays using a monoclonal antibody that recognizes wild-type LH only with those of another assay using a polyclonal antibody that recognizes equally both variant and wild-type LH (total LH). The ratio of variant LH to total LH (LH ratio) was used to determine the serum LH status., Results: The LH ratio in the control group showed the peak 15 min after GnRH injection, while that in the patient group showed the peaks 30-60 min after injection. The LH ratio in the patient group at 120 min after injection was significantly lower than that in the control group. The percent increases in LH ratio in both groups showed the peak 15 min after injection. The patient group had significantly lower changes of LH ratio at 15, 60, 90 and 120 min after GnRH injection compared with that in the control group., Conclusion: Differences in circulatory kinetics of the two types of LH may explain the differences in LH function between patients with ovulatory disorders and women with normal ovulatory cycles., (Copyright 2004 S. Karger AG, Basel)

Metaphase chromosomes from three reciprocal translocation carriers were examined by scanning electron microscopy. A gap was detected in one of the two derivative chromosomes in each carrier. The position of each gap was identical with that of the respective breakpoint of the derivative chromosome to which the longer chromosome fragment was translocated. The gap length resembled a midsize G-band. Our observations suggest that derivative chromosomes of reciprocal translocations involve aberrations of a high-ordered structure of chromatid fibers at the translocation sites.

To understand endocrine function and to determine which endocrine systems are likely to be affected, 6 patients with mitochondrial encephalomyopathies were studied. Three patients had myoclonus epilepsy and ragged-red fibers, and the other 3 patients had mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes. Clinically, short stature (5/6), amenorrhea (2/3), impotency (3/3), and poor development of secondary sexual characteristics (4/6) were noted. The endocrinological studies including triiodothyronine, tetraiodothyronine, thyrotropin, adrenocorticotropin, cortisol, parathyroid hormone and blood sugar were normal. However, there were low serum concentrations of estradiol (2), and progesterone (2) in 3 female patients. Two patients (1 man and 1 woman) had growth hormone deficiency and 1 had low testosterone level. Hypothalamopituitary dysfunction was confirmed after a series of stimulation tests. We conclude that patients with mitochondrial encephalomyopathies are common to have gonadal dysfunction. Although target organ may play a role, hypothalamopituitary lesion may be responsible for this abnormality.

We report a successful twin pregnancy in a woman with secondary amenorrhea who is genotypically 47,XXX. Cytogenetic markers suggested that they are apparently monozygotic twins.

A Mexican 181/2-year-old girl with short stature, primary amenorrhea, and mild Turner stigmata was found to have a 45,X/46,X,ter rea(X;X)(p22.3;p22.3) karyotype in her lymphocytes. The rearranged chromosome was twice the size of a normal X, appeared to be attached head-to-head, had no detectable chromatin loss, only one primary constriction, constitutive heterochromatin at both the centromere and pseudocentromere regions, was mitotically stable, and always showed late replication. From the analysis of this and other X;X terminal rearrangements we draw four conclusions: (1) Terminal rearrangements may arise either by telomeric fusion (tel fus) without loss of genetic material or from a conventional telomeric translocation. (2) Telomeric fusions between homologous chromosomes (the commonest type) can be secondary to impaired telomeric replication. (3) Phenotypically, patients with an X;X terminal rearrangement show great variability which depends mainly on whether or not chromatin has been lost in the rejoining process and a 45,X clone. (4) Patients with an X;X telomeric fusion without mosaicism are likely to have an XXX phenotype, whereas turneroid features are expected in mixoploidies that include an X monosomic clone and in cases of translocations involving the short arms.

An unbalanced X-autosome translocation was observed in a patient with primary amenorrhea, Turner phenotype and bilateral streak gonads. The karyotype of the proposita was 45,X,-X,+der(6),t(X;6). Autoradiography and BUDR pretreatment revealed differential inactivation of the X chromosomes. Sex chromatin pattern was in good agreement with the types of the X inactivation. Our finding brings out some further questions regarding inactivation of the human X chromosome and the human X chromosome and the related phenotypical changes.

A woman with primary amenorrhea and pure gonadal dysgenesis had two cytogenetically abnormal cell lines. The karyotype was 45,X in 56--95% of mitosis from lymphocytes and skin fibroblasts. In the remaining 5--44% of the cells there was, in addition to a normal X, a structurally abnormal X chromosome interpretable as pter leads to q21::q11 leads to pter or pter leads to q21::q13 leads to pter. The abnormal X chromosome was heterocyclic and had a normal centromere plus an extra C band in the long arm. Detailed interpretation of the structural rearrangements of this chromosome required the use of both Q-, G-, and C-banding and the BrdU-Hoechst 33258 technique.

Three X/autosomal translocations, two familial and one de novo, were analyzed. Late-replicating chromosomes and chromosome regions were studied with R-banding techniques after BrdU incorporation. The first translocation, t(X;4)(q21;q13), was a de novo translocation, found in a woman with amenorrhea. The structurally normal X was late replicating in all cells. The second translocation, t(X;6)(p21;q26), was found in an unbalanced form, 46,XX,der(6), in a phenotypically abnormal girl; her mother carried the balanced translocation. In the mother's blood culture inactivation of the X's followed two modes: In 85% of the cells the normal X was late replicating, and in the remaining 15% the der(X) was inactivated, including the attached fragment of chromosome 6. The third translocation, t(X;17)(p11;q24), was found in three generations. In the phenotypically normal mother, who carried the balanced translocation, the late-replicating X was always the normal X. In her daughters, who had an unbalanced karyotype, 46,X,der(X), and multiple congenital abnormalities, the X part of the translocation chromosome was always late replicating. No spreading of inactivation over the attached autosomal region was observed, resulting for these patients in a partial trisomy of 17q. Their peculiar phenotype is described.

Segregation after mitotic crossing-over in an isodicentric (idic) X chromosome with one active and one inactive centromere has given rise to two new cell lines, one in which the idic(Xpter) chromosome has two active centromeres (most of these chromosomes also have an inversion) and another in which neither centromere is active. The two X chromosomes are attached at the telomeres of their short arms. Similar segregation has given rise to two other cell lines with idic(Xq-) chromosomes. Other observations on segregation after mitotic crossing-over are reviewed. Unequal crossing-over has apparently played a major role in the evolution of various genes and heterochromatin. Retinoblastoma and Wilms tumor are in some cases associated with homozygosity of a chromosome segment resulting from mitotic crossing-over. Similarly, the high incidence of cancer in Bloom syndrome may be caused by mitotic crossing-over leading to homozygosity or amplification of oncogenes.

An X;X chromosomal translocation was ascertained by conventional cytogenetic analysis in a phenotypically normal woman with secondary amenorrhea. In situ hybridization was performed with previously mapped X-specific DNA sequences to study the rearrangement at the molecular level. The results allowed us to demonstrate that the subject is monosomic for the distal region of the short arm of the X and trisomic for the distal region of the long arm.

A patient with primary amenorrhea and a terminal rearrangement of chromosomes 13 and 20 is described. The stability of the dicentric translocation chromosome was achieved by suppression of the activity of the centromere of chromosome 20 and actual deletion of the centromere of chromosome 13. These two mechanisms may be fundamentally similar if centromere inactivation results from a visually undetectable deletion.