The Role of SRY Mutations in the Etiology of Gonadal Dysgenesis in Patients with 45,X/46,XY Disorder of Sex Development and Variants

Background: The potential involvement of SRY in abnormal gonadal development in 45,X/46,X,der(Y) patients was proposed following the identification of SRY mutations in a few patients with Turner syndrome (TS). However, its exact etiological role in gonadal dysgenesis in patients with Y chromosome mosaicisms has not yet been clarified. Aims: It was the aim of this study to screen for allelic variation in SRY in a large cohort of patients with disorders of sex development due to chromosomal abnormalities with 45, X/46, X, der(Y) karyotype. Patients: Twenty-seven patients, 14 with TS and 13 with mixed gonadal dysgenesis (MGD), harboring 45, X/46, X, der(Y) karyotypes were selected. Methods: Genomic DNA was extracted from peripheral blood leukocytes of all patients and from gonadal tissue in 4 cases. The SRY coding region was PCR amplified and sequenced. Results: We identified only 1 polymorphism (c.561C -> T) in a 45,X/46,XY MGD patient, which was detected in blood and in gonadal tissue. Conclusion: Our results indicate that mutations in SRY are rare findings in patients with Y chromosome mosaicisms. Therefore, a significant role of mutated SRY in the etiology of gonadal dysgenesis in patients harboring 45, X/46, XY karyotype and variants seems very unlikely. Copyright (C) 2010 S. Karger AG, Basel

46,XY disorders of sex development (DSD)

The term disorders of sex development (DSD) includes congenital conditions in which development of chromosomal, gonadal or anatomical sex is atypical. Mutations in genes present in X, Y or autosomal chromosomes can cause abnormalities of testis determination or disorders of sex differentiation leading to 46,XY DSD. Detailed clinical phenotypes allow the identification of new factors that can alter the expression or function of mutated proteins helping to understand new undisclosed biochemical pathways. In this review we present an update on 46,XY DSD aetiology, diagnosis and treatment based on extensive review of the literature and our three decades of experience with these patients.

Melatonin in maturation media fails to improve oocyte maturation, embryo development rates and DNA damage of bovine embryos

Melatonin (MEL) acts as a powerful scavenger of free radicals and direct gonadal responses to melatonin have been reported in the literature. Few studies, however, have evaluated the effect of MEL during in vitro maturation (IVM) on bovine embryos. This study tested the addition of MEL to maturation medium (MM) with no gonadotropins on nuclear maturation and embryo development rates and the incidence of DNA damage in resulting embryos. Cumulus-oocyte complexes were aspirated from abattoir ovaries and cultured in MM (TCM-199 medium supplemented with 10% fetal calf serum - FCS) at 39ºC and 5% CO2 in air. After 24 hours of culture in MM with 0.5 µg mL-1 FSH and 5.0 µg mL-1 LH; 10-9 M MEL) or 10-9 M MEL, 0.5 µg mL-1 FSH and 5.0 µg mL-1 LH, the oocytes were stained with Hoechst 33342 to evaluate nuclear maturation rate. After in vitro fertilization and embryo culture, development rates were evaluated and the blastocysts were assessed for DNA damage by Comet assay. There was no effect of melatonin added to the MM, alone or in combination with gonadotropins, on nuclear maturation, cleavage and blastocyst rates. These rates ranged between 88% to 90%, 85% to 88% and 42% to 46%, respectively. The extent of DNA damage in embryos was also not affected by MEL supplementation during IVM. The addition of 10-9 M MEL to the MM failed to improve nuclear maturation and embryo development rates and the incidence of DNA damage in resulting embryos, but was able to properly substitute for gonadotropins during IVM.

Structure of (46)Ti at low excitation energy

The nucleus (46)Ti has been studied with the reaction (42)Ca((7)Li,p2n)(46)Ti at a bombarding energy of 31 MeV. Thin target foils backed with a thick Au layer were used. Five new levels of negative parity were observed. Several lifetimes have been determined with the Doppler shift attenuation method. Low-lying experimental negative-parity levels are assigned to three bands with K(pi) = 3, 0, and 4, which are interpreted in terms of the large-scale shell model, considering particle-hole excitations from d(3/2) and s(1/2) orbitals. Shell model calculations were performed using a few effective interactions. However, good agreement was not achieved in the description of either negative- or positive-parity low-lying levels.

Alterations triggered by steroid gonadal hormones in triglycerides and the cellular immune response of Calomys callosus infected with the Y strain of Trypanosoma cruzi

Calomys callosus is a wild rodent found naturally infected with different Trypanosoma cruzi strains. In the work described here, groups of male and female C callosus were subjected to orchiectomy, ovariectomy and sham operation. One month after surgery, animals were inoculated intraperitoneally (i.p.) with 4 x 10(4) blood trypomastigotes of the ""Y"" strain of T. cruzi. Parasitemia, triglycerides, nitric oxide (NO) and concanavalin A (ConA)-induced proliferation were evaluated. Parasitemia during the course of infection was significantly higher in infected and sham operated animals as compared to infected orchiectomized animals. The opposite was observed in the ovariectomized and infected group. Orchiectomized and infected animals displayed elevated triglyceride levels, as well as a more vigorous immune response, with higher splenocyte proliferation and elevated concentrations of NO. Ovariectomy resulted in an impaired immune response, as observed by a reduction of splenocyte proliferation and NO concentration. The results suggest a pivotal role for gonadal hormones in the modulation of triglyceride levels and the magnitude of the immune response during the acute phase of T. cruzi infection. (C) 2008 Published by Elsevier B.V.

46,XY DSD due to impaired androgen production

Disorders of androgen production can occur in all steps of testosterone biosynthesis and secretion carried out by the foetal Leydig cells as well as in the conversion of testosterone into dihydrotestosterone (DHT). The differentiation of Leydig cells from mesenchymal cells is the first walk for testosterone production. In 46,XY disorders of sex development (DSDs) due to Leydig cell hypoplasia, there is a failure in intrauterine and postnatal virilisation due to the paucity of interstitial Leydig cells to secrete testosterone. Enzymatic defects which impair the normal synthesis of testosterone from cholesterol and the conversion of testosterone to its active metabolite DHT are other causes of DSD due to impaired androgen production. Mutations in the genes that codify the enzymes acting in the steps from cholesterol to DHT have been identified in affected patients. Patients with 46,XY DSD secondary to defects in androgen production show a variable phenotype, strongly depending of the specific mutated gene. Often, these conditions are detected at birth due to the ambiguity of external genitalia but, in several patients, the extremely undervirilised genitalia postpone the diagnosis until late childhood or even adulthood. These patients should receive long-term care provided by multidisciplinary teams with experience in this clinical management. (C) 2009 Elsevier Ltd. All rights reserved.

A novel WT1 heterozygous nonsense mutation (p.K248X) causing a mild and slightly progressive nephropathy in a 46,XY patient with Denys-Drash syndrome

WT1 mutations have been described in a variety of syndromes, including Denys-Drash syndrome (DDS), which is characterized by predisposition to Wilms` tumor, genital abnormalities and development of early nephropathy. The most frequent WT1 defects in DDS are missense mutations located in exons 8-9. Our aim is to report a novel WT1 mutation in a 46,XY patient with a DDS variant, who presented a mild nephropathy with a late onset diagnosed during adolescence. He had ambiguous genitalia at birth. At 4 months of age he underwent nephrectomy (Wilms` tumor) followed by chemotherapy. Ambiguous genitalia were corrected and bilateral gonadectomy was performed. Sequencing of WT1 identified a novel heterozygous mutation (c.742A > T) in exon 4 that generates a premature stop codon (p.K248X). Interestingly, this patient has an unusual DDS nephropathy progression, which reinforces that patients carrying WT1 mutations should have the renal function carefully monitored due to the possibility of late-onset nephropathy.

Chondrosarcoma of Bone Lessons From 46 Operated Cases in a Single Institution

Background Bone chondrosarcomas are rare malignant tumors that have variable biologic behavior, and their treatment is controversial. For low-grade tumors, there is no consensus on whether intralesional en bloc resections are the best treatment. Questions/purposes We therefore compared patients with Grade 1 and Grade 2 primary central chondrosarcomas to (1) determine difference in survival and (2) local recurrence rates; and (3) determine any association of histological grade with some clinical and demographic characteristics. Methods We retrospectively reviewed 46 patients with grade 1 and 2 chondrosarcomas. There were 25 men and 21 women with a mean age of 43 years (range, 17-79 years). Minimum followup was 32 months (mean, 99 months; range, 32-312 months) for the patients who remained alive in the end of the study. Twenty-three of the tumors were intracompartmental (Enneking A); of these, 19 were Grade 1 and 4 were Grade 2. Twenty-three tumors were extracompartmental (Enneking B); of these, 4 were Grade 1 and 19 were Grade 2. Twenty-five patients underwent intralesional resection, 18 had wide resection, and three had amputations. Results The overall survival rate was 94% and the disease-free survival rate was 90%. Among the 23 Grade 1 tumors, we observed six local recurrences and none of these patients died; among the 23 Grade 2 tumors, 10 recurred and two patients died. Local recurrence negatively influenced survival. Conclusions For lesions with radiographic characteristics of intracompartmental Grade 1 chondrosarcoma, we believe intralesional resection followed by electrocauterization and cement is the best treatment. When the imaging suggests aggressive (Grade 2 or 3) chondrosarcoma, then wide resection is promptly indicated.