Mutations In SRY Research Articles

Extensive clinical, hormonal and genetic screening in a large consecutive series of 46,XY neonates and infants with atypical sexual development.

BackgroundOne in 4500 children is born with ambiguous genitalia, milder phenotypes occur in one in 300 newborns. Conventional time-consuming hormonal and genetic work-up provides a genetic diagnosis in around 20-40% of 46,XY cases with ambiguous genitalia. All others remain without a definitive diagnosis. The investigation of milder cases, as suggested by recent reports remains controversial.MethodsIntegrated clinical, hormonal and genetic screening was performed in a sequential series of 46, XY children, sex-assigned male, who were referred to our pediatric endocrine service for atypical genitalia (2007–2013).ResultsA consecutive cohort of undervirilized 46,XY children with external masculinization score (EMS) 2–12, was extensively investigated. In four patients, a clinical diagnosis of Kallmann syndrome or Mowat-Wilson syndrome was made and genetically supported in 2/3 and 1/1 cases respectively. Hormonal data were suggestive of a (dihydro)testosterone biosynthesis disorder in four cases, however no HSD17B3 or SRD5A2 mutations were found. Array-CGH revealed a causal structural variation in 2/6 syndromic patients. In addition, three novel NR5A1 mutations were found in non-syndromic patients. Interestingly, one mutation was present in a fertile male, underlining the inter- and intrafamilial phenotypic variability of NR5A1-associated phenotypes. No AR, SRY or WT1 mutations were identified.ConclusionOverall, a genetic diagnosis could be established in 19% of non-syndromic and 33% of syndromic cases. There is no difference in diagnostic yield between patients with more or less pronounced phenotypes, as expressed by the external masculinisation score (EMS). The clinical utility of array-CGH is high in syndromic cases. Finally, a sequential gene-by-gene approach is time-consuming, expensive and inefficient. Given the low yield and high expense of Sanger sequencing, we anticipate that massively parallel sequencing of gene panels and whole exome sequencing hold promise for genetic diagnosis of 46,XY DSD boys with an undervirilized phenotype.Electronic supplementary materialThe online version of this article (doi:10.1186/s13023-014-0209-2) contains supplementary material, which is available to authorized users.

Structure-Function Relationships in Human Testis-determining Factor SRY: AN AROMATIC BUTTRESS UNDERLIES THE SPECIFIC DNA-BENDING SURFACE OF A HIGH MOBILITY GROUP (HMG) BOX*♦

Human testis determination is initiated by SRY, a Y-encoded architectural transcription factor. Mutations in SRY cause 46 XY gonadal dysgenesis with female somatic phenotype (Swyer syndrome) and confer a high risk of malignancy (gonadoblastoma). Such mutations cluster in the SRY high mobility group (HMG) box, a conserved motif of specific DNA binding and bending. To explore structure-function relationships, we constructed all possible substitutions at a site of clinical mutation (W70L). Our studies thus focused on a core aromatic residue (position 15 of the consensus HMG box) that is invariant among SRY-related HMG box transcription factors (the SOX family) and conserved as aromatic (Phe or Tyr) among other sequence-specific boxes. In a yeast one-hybrid system sensitive to specific SRY-DNA binding, the variant domains exhibited reduced (Phe and Tyr) or absent activity (the remaining 17 substitutions). Representative nonpolar variants with partial or absent activity (Tyr, Phe, Leu, and Ala in order of decreasing side-chain volume) were chosen for study in vitro and in mammalian cell culture. The clinical mutation (Leu) was found to markedly impair multiple biochemical and cellular activities as respectively probed through the following: (i) in vitro assays of specific DNA binding and protein stability, and (ii) cell culture-based assays of proteosomal degradation, nuclear import, enhancer DNA occupancy, and SRY-dependent transcriptional activation. Surprisingly, however, DNA bending is robust to this or the related Ala substitution that profoundly impairs box stability. Together, our findings demonstrate that the folding, trafficking, and gene-regulatory function of SRY requires an invariant aromatic "buttress" beneath its specific DNA-bending surface.

Abstract 249: Male Mice with XX Sex Chromosome Complement Exhibit Reduced Angiotensin II-Induced Hypertension and Atherosclerosis

Objective: Hypertension and atherosclerosis exhibit sexual dimorphism, partially ascribed to effects of sex hormones. However, recent studies suggest that sex chromosome complement may also contribute to sexual dimorphism of these diseases. The renin-angiotensin system has been suggested to contribute to sexual dimorphism of hypertension and atherosclerosis. However, the relative contribution of sex hormones, versus chromosomes, in the regulation of angiotensin II (AngII)-mediated responses is unknown. We hypothesized that the presence of an XX chromosome complement in male hyperlipidemic mice would reduce AngII-induced hypertension and atherosclerosis. Methods and Results: Male Ldlr-/- mice with an Sry mutation but with an Sry transgene on autosomes were bred to Ldlr-/- females to generate XY or XX males. Male XY or XX mice were segregated to sham-operated or orchiectomized (ORC) groups and fed a high fat diet (42% kcal from fat). Two weeks later, mice were infused with AngII (1,000 ng/kg/min) for 4 weeks. In the presence of sex hormones (sham groups), systolic blood pressure (SBP) was significantly lower in AngII-infused XX than XY males (XY, 136 ± 4; XX, 119 ± 4 mmHg, p=0.024). In XY males, ORC had no significant effect on SBP compared to sham (ORC XY, 129 ± 6 mmHg; p=0.48). However, following castration of XX males, SBP significantly increased (ORC XX 135 ± 3 mmHg; p =0.002). In XY males, ORC resulted in a significant increase in atherosclerotic lesion surface area in the aortic arch (sham, 19 ± 4; ORC, 32 ± 7%; p=0.04). In contrast, ORC had no significant effect on lesion surface area in XX males (sham, 17 ± 3; ORC, 15 ± 2%; p=0.53). Moreover, in the absence of sex hormones, lesion surface area was markedly increased in XY compared to XX males (XY, 32 ± 7; XX, 15 ± 2%; p=0.002). Conclusions: These results demonstrate that effects of testosterone to regulate AngII-induced hypertension and atherosclerosis are dependent on sex chromosome complement. In XY males, testosterone protects against AngII-induced atherosclerosis. In XX males, testosterone protects against AngII-induced hypertension. Moreover, there is pronounced effect of XY chromosome complement to promote AngII-induced atherosclerosis in males.

Investigation of mutations in the SRY, SOX9, and DAX1 genes in sex reversal patients from the Sichuan region of China

We investigated the molecular genetic mechanism of sex reversal by exploring the relationship between mutations in the sex-determining genes SRY, SOX9, and DAX1 with genetic sex reversal disease. Mutations in the three key genes were detected by polymerase chain reaction (PCR) and sequencing after karyotype analysis. The mutations detected were then aligned with a random sample of 100 normal sequences and the NCBI sequence database in order to confirm any new mutations. Furthermore, the copy number of SOX9 was measured by fluorescence quantitative PCR. Seven of the 10 male sex reversal patients (46, XX) contained an excess copy of the SRY gene, while one of the eight female sex reversal patients (46, XY) was lacking the SRY gene. Additionally, a new mutation (T-A, Asp24Lys) was detected in one female sex reversal patient (46, XY). No other mutation was detected in the analysis of SOX9 and DAX1, with the exception of an insertion mutation (c.35377791insG) found in the testicular-specific enhancer (TESCO) sequences in an SRY-positive female sex reversal patient (46, XY). Eight of the 18 sex reversal cases (44.4%) showed obvious connections with SRY gene translocations, mutations, or deletions, which was significantly higher than that reported previously (33.3%), indicating a need to further expand the range of sample collection. Overall, these results indicated that the main mechanism of sex reversal are not associated with mutations in the coding regions of SOX9 and DAX1 or copy number variations of SOX9, which is consistent with results of previous studies.

Anomalies of 46, XY Sexual Differentiation-The Role of SRY and NR5A1

Anomalies of 46, XY Sexual Differentiation-The Role of SRY and NR5A1 Objective: To screen for mutations in the SRY and NR5A1 genes in patients with 46, XY disorder of sex development (DSD) dysgenesis. Patients and methods: Genomic DNA from10 patients with 46, XY DSD dysgenesis was obtained from peripheral blood leukocytes to study NR5A1 and SRY mutations. Results: Two patients presented mutations in the NR5A1 gene. Two mutations were in the hinge domain: c369 G>C (pgly 123 Ala) and c387 C>T (pPro 129 Leu); the pGly 123 Ala mutation was not pathologic. Another mutation involved one stop codon at position 404 of the NR5A1 protein, resulting in a truncated protein with only 404 amino acids. Conclusion: A likely molecular etiology was found in two of the ten 46, XYDSD patients evaluated: c387 C>T (pPro129 Leu) and ptyr404 stop.

Genomic Contingency and Protein Evolution: Accelerated Divergence of a DNA-Binding Module due to an Adjoining Micro-Satellite Invasion

The sex-determining region of the mammalian Y chromosome encodes an architectural transcription factor containing a conserved sequence-specific high-mobility-group (HMG) box. Designated SRY, transient expression of this gene in the fetal gonadal ridge leads to Sertoli-cell differentiation and in turn testis formation. Mutations in human SRY are associated with 46, XY pure gonadal dysgenesis and somatic sex reversal. We have investigated the evolutionary history of SRY and its protein product SRY among placental mammals as a model for the conservation and divergence of a sequence-specific DNA-binding and DNA-bending module (the HMG box). Remarkably, the rate of divergence among mammalian SRY genes is markedly more rapid in Rodentia than among other Orders of placental mammals. Evidence will be provided that this accelerated evolution is a consequence of the in-frame insertion of a CAG triplet-expansion micro-satellite element, encoding a poly-glutamine or poly-alanine domain with autonomous biochemical properties. A model is proposed wherein relaxation of selective pressure on the HMG box has led to accumulation of deleterious amino-acid substitutions. Thus, a contingency of genomic dynamics (micro-satellite invasion) has led to a change in the pace of the mutational clock governing the evolution of a DNA-binding module.

SRY mutation analysis by next generation (deep) sequencing in a cohort of chromosomal Disorders of Sex Development (DSD) patients with a mosaic karyotype

BackgroundThe presence of the Y-chromosome or Y chromosome-derived material is seen in 4-60% of Turner syndrome patients (Chromosomal Disorders of Sex Development (DSD)). DSD patients with specific Y-chromosomal material in their karyotype, the GonadoBlastoma on the Y-chromosome (GBY) region, have an increased risk of developing type II germ cell tumors/cancer (GCC), most likely related to TSPY. The Sex determining Region on the Y gene (SRY) is located on the short arm of the Y-chromosome and is the crucial switch that initiates testis determination and subsequent male development. Mutations in this gene are responsible for sex reversal in approximately 10-15% of 46,XY pure gonadal dysgenesis (46,XY DSD) cases. The majority of the mutations described are located in the central HMG domain, which is involved in the binding and bending of the DNA and harbors two nuclear localization signals. SRY mutations have also been found in a small number of patients with a 45,X/46,XY karyotype and might play a role in the maldevelopment of the gonads.MethodsTo thoroughly investigate the presence of possible SRY gene mutations in mosaic DSD patients, we performed next generation (deep) sequencing on the genomic DNA of fourteen independent patients (twelve 45,X/46,XY, one 45,X/46,XX/46,XY, and one 46,XX/46,XY).Results and conclusionsThe results demonstrate that aberrations in SRY are rare in mosaic DSD patients and therefore do not play a significant role in the etiology of the disease.

Organizational and Functional Status of the Y-linked Genes and Loci in the Infertile Patients Having Normal Spermiogram

Male fertility is an orchestrated interplay of loci on the Y chromosome with a number of genes from across the other chromosomes. In this context, micro-deletions in the Y chromosome have been correlated with spermatogenic failure often leading to infertility. However, causes of infertility in the patients with the normal spermiogram have remained unclear and therefore pose another level of challenge. In the present study, we analyzed 64 STSs, studied different Y-linked genes and loci and conducted single nucleotide variant (SNV) analyses in 31 infertile males with normal spermiogram along with 67 normal fertile males (NFMs) to gain an insight into the organization of their Y chromosome. Further, employing quantitative real-time PCR (qPCR), we studied copy number variation of DYZ1 arrays and three genes and mutational status of SRY by direct sequence analyses. STS analyses of the AZFa, b and c regions in these patients showed known and new mutations. Further, copies of DAZ and BPY2 in the patients were found to be affected compared to those in NFMs. All the patients had normal copy number of the SRY however its sequence analysis (in silico) showed mutations in eight patients. In four of these eight patients, SRY mutations resulted into truncated proteins. Similarly, DYZ1 analysis showed micro-deletions and it's much reduced copy number as compared to those in NFMs. Present study in males with unexplained infertility revealed deletions similar to those observed in oligospermic and azoospermic patients. Thus, there are some common but still unknown factors underlying infertility in these patients irrespective of their spermatogenic status. This work is envisaged to augment DNA diagnosis, proving beneficial in the context of in vitro fertilization (IVF) and genetic counselling.

A 46,XY Female DSD Patient with Bilateral Gonadoblastoma, a Novel SRY Missense Mutation Combined with a WT1 KTS Splice-Site Mutation

Patients with Disorders of Sex Development (DSD), especially those with gonadal dysgenesis and hypovirilization are at risk of developing malignant type II germ cell tumors/cancer (GCC) (seminoma/dysgerminoma and nonseminoma), with either carcinoma in situ (CIS) or gonadoblastoma (GB) as precursor lesion. In 10–15% of 46,XY gonadal dysgenesis cases (i.e., Swyer syndrome), SRY mutations, residing in the HMG (High Mobility Group) domain, are found to affect nuclear transport or binding to and bending of DNA. Frasier syndrome (FS) is characterized by gonadal dysgenesis with a high risk for development of GB as well as chronic renal failure in early adulthood, and is known to arise from a splice site mutation in intron 9 of the Wilms’ tumor 1 gene (WT1). Mutations in SRY as well as WT1 can lead to diminished expression and function of SRY, resulting in sub-optimal SOX9 expression, Sertoli cell formation and subsequent lack of proper testicular development. Embryonic germ cells residing in this unfavourable micro-environment have an increased risk for malignant transformation. Here a unique case of a phenotypically normal female (age 22 years) is reported, presenting with primary amenorrhoea, later diagnosed as hypergonadotropic hypogonadism on the basis of 46,XY gonadal dygenesis with a novel missense mutation in SRY. Functional in vitro studies showed no convincing protein malfunctioning. Laparoscopic examination revealed streak ovaries and a normal, but small, uterus. Pathological examination demonstrated bilateral GB and dysgerminoma, confirmed by immunohistochemistry. Occurrence of a delayed progressive kidney failure (focal segmental glomerular sclerosis) triggered analysis of WT1, revealing a pathogenic splice–site mutation in intron 9. Analysis of the SRY gene in an additional five FS cases did not reveal any mutations. The case presented shows the importance of multi-gene based diagnosis of DSD patients, allowing early diagnosis and treatment, thus preventing putative development of an invasive cancer.

46, XY gonadal dysgenesis: new SRY point mutation in two siblings with paternal germ line mosaicism

Familial recurrence risks are poorly understood in cases of de novo mutations. In the event of parental germ line mosaicism, recurrence risks can be higher than generally appreciated, with implications for genetic counseling and clinical practice. In the course of treating a female with pubertal delay and hypergonadotropic hypogonadism, we identified a new missense mutation in the SRY gene, leading to somatic feminization of this karyotypically normal XY individual. We tested a younger sister despite a normal onset of puberty, who also possessed an XY karyotype and the same SRY mutation. Imaging studies in the sister revealed an ovarian tumor, which was removed. DNA from the father's blood possessed the wild type SRY sequence, and paternity testing was consistent with the given family structure. A brother was 46, XY with a wild type SRY sequence strongly suggesting paternal Y-chromosome germline mosaicism for the mutation. In disorders of sexual development (DSDs), early diagnosis is critical for optimal psychological development of the affected patients. In this case, preventive karyotypic screening allowed early diagnosis of a gonadal tumor in the sibling prior to the age of normal puberty. Our results suggest that cytological or molecular diagnosis should be applied for siblings of an affected DSD individual.

Complete gonadal dysgenesis in clinical practice: the 46,XY karyotype accounts for more than one third of cases

To determine the frequency of XY karyotypes among females with complete gonadal dysgenesis (CGD) and to investigate the frequency of both gonadal tumors and SRY mutations. Retrospective study based on data from all patients with CGD seen in our service from 1989 to 2010. Clinic for disorders of sex development, University Hospital, State University of Campinas. Thirty-two patients with hypergonadotropic hypogonadism, streak gonads, internal and external female genitalia, and normal karyotype (46,XX or 46,XY); 31 were index cases and 29 did not have a previously determined karyotype. None. None. The percentage of XY karyotypes among patients with CGD was 34.5% (10/29). Mean age at diagnosis among XY and XX patients was 17.4 years and 19.9 years, respectively. Gonadal tumors were found in 4 of 9 XY girls, and 7 of 10 had SRY gene mutations. The previously unreported finding of an elevated frequency of 46,XY karyotype among patients with CGD and the high risk of gonadal neoplasia in such cases indicate that this diagnosis must be kept in mind by clinicians and strengthen the importance of karyotype analysis in females with primary hypogonadism. In addition, the frequency of SRY mutations in XY CGD might be higher than previously considered.

Mammalian Testis-determining Factor SRY and the Enigma of Inherited Human Sex Reversal: FRUSTRATED INDUCED FIT IN A BENT PROTEIN-DNA COMPLEX

Mammalian testis-determining factor SRY contains a high mobility group box, a conserved eukaryotic motif of DNA bending. Mutations in SRY cause XY gonadal dysgenesis and somatic sex reversal. Although such mutations usually arise de novo in spermatogenesis, some are inherited and so specify male development in one genetic background (the father) but not another (the daughter). Here, we describe the biophysical properties of a representative inherited mutation, V60L, within the minor wing of the L-shaped domain (box position 5). Although the stability and DNA binding properties of the mutant domain are similar to those of wild type, studies of SRY-induced DNA bending by subnanosecond time-resolved fluorescence resonance energy transfer (FRET) revealed enhanced conformational fluctuations leading to long range variation in bend angle. (1)H NMR studies of the variant protein-DNA complex demonstrated only local perturbations near the mutation site. Because the minor wing of SRY folds on DNA binding, the inherited mutation presumably hinders induced fit. Stopped-flow FRET studies indicated that such frustrated packing leads to accelerated dissociation of the bent complex. Studies of SRY-directed transcriptional regulation in an embryonic gonadal cell line demonstrated partial activation of downstream target Sox9. Our results have demonstrated a nonlocal coupling between DNA-directed protein folding and protein-directed DNA bending. Perturbation of this coupling is associated with a genetic switch poised at the threshold of activity.

A novel mutation of SRY gene identified in a 46,XY complete gonadal dysgenesis patient

The clinical and genetic characteristics in a patient with 46,XY complete gonadal dysgenesis was investigated. Clinical features and laboratory data were collected from the patient and the family. The exon of SRY gene was amplified by PCR and sequenced. The patient presented with primary amenorrhea, nonambiguous female external genitalia, slight breast development, and no axillary hair or pubic hair. The female internal reproductive organs consisted of uterus and streaks of ovarian tissue. Howerver, the chromosome karyotype was 46,XY. A missense mutation of A66T in SRY gene was identified, which was not previously reported. The novel SRY mutation caused the sex reversal in this 46,XY female patient. Key words: Sex reversal; Complete gonadal dysgenesis; Swyer syndrome; SRY gene; Mutation

Inhibition of SRY-Calmodulin Complex Formation Induces Ectopic Expression of Ovarian Cell Markers in Developing XY Gonads

The transcription factor sex-determining region of the Y chromosome (SRY) plays a key role in human sex determination, because mutations in SRY cause disorders of sex development in XY individuals. During gonadal development, Sry in pre-Sertoli cells activates Sox9 gene transcription, committing the fate of the bipotential gonad to become a testis rather than an ovary. The high-mobility group domain of human SRY contains two independent nuclear localization signals, one bound by calmodulin (CaM) and the other by importin-β. Although XY females carry SRY mutations in these nuclear localization signals that affect SRY nuclear import in transfected cells, it is not known whether these transport mechanisms are essential for gonadal development and sex determination. Here, we show that mouse Sry protein binds CaM and that a CaM antagonist reduces CaM binding, nuclear accumulation, and transcriptional activity of Sry in transfected cells. CaM antagonist treatment of cultured, sexually indifferent XY mouse fetal gonads led to reduced expression of the Sry target gene Sox9, defects in testicular cord formation, and ectopic expression of the ovarian markers Rspondin1 and forkhead box L2. These results indicate the importance of CaM for SRY nuclear import, transcriptional activity, testis differentiation, and sex determination.

Identification of novel SRY mutations and SF1 (NR5A1) changes in patients with pure gonadal dysgenesis and 46,XY karyotype

Primary amenorrhea due to 46,XY disorders of sexual development (DSD) is complex with the involvement of several genes. Karyotyping of such patients is important as they may develop dysgerminoma and molecular analysis is important to identify the underlying mechanism and explore the cascade of events occurring during sexual development. The present study was undertaken for the genetic analysis in seven patients from five families presenting with primary amenorrhea and diagnosed with pure gonadal dysgenesis. Karyotyping was done and the patients were screened for underlying changes in SRY, desert hedgehog (DHH), DAX1 (NR0B1) and SF1 (NR5A1) genes, mutations in which are implicated in DSD. All the patients had 46,XY karyotype and two novel SRY mutations were found. In Family 1 (Patient S1.1) a missense mutation c.294G>A was seen, which results in a stop codon at the corresponding amino acid (Trp98X) and in Family 2 (Patients S2.1, S2.2 and S2.3), a missense mutation c.334G>A (Glu112Leu) was identified in all affected sisters. Both mutations were seen to occur in the conserved high mobility group box of SRY gene. One heterozygous change c.427G>A resulting in Glu143Lys in DHH gene in one patient and two heterozygous changes in the intronic region of SF1 (NR5A1) gene (c.244+80G>A+ c.1068-20C>T) in another patient were noted. One individual did not show changes in any of the genes analyzed. These results reiterate the importance of SRY and others, such as SF1 (NR5A1) and DHH, that are involved in the cascade of events leading to sex determination and also their role in sex reversal.

A novel 15bp micro-duplication in SF-1 gene showing diverse phenotypic spectrum in a Chinese family

Objective. To determine the genetic cause of sex reversal in a Chinese family.Methods. Two sisters aged 21 and 20 years old were referred for primary amenorrhoea and poor secondary sexual development. They were subjected to clinical, endocrinologic and ultrasonographic investigation, and molecular analysis including cytogenetics, array CGH, SRY and SF-1 mutation screening.Results. A novel 15bp micro-duplication in the SF-1 gene in patients affected by 46,XY sex-reversal phenotype without dysgenesis.Conclusion. The novel 15bp duplication of SF-1 gene affecting 46,XY females with diverse phenotypic spectrum. This provides new information for genetic counselling of disorders of sex development.

Novel DMRT1 3'UTR+11insT mutation associated to XY partial gonadal dysgenesis

The Y-chromosome-located SRY gene encodes a small testis-specific protein containing a DNA-binding motif known as the HMG (high mobility group) box. However, mutations in SRY are not frequent especially in cases of 46,XY partial gonadal dysgenesis. Several sex-determining genes direct the fate of the bipotential gonad to either testis or ovary. In addition, heterozygous small deletions in 9p can cause complete and partial XY gonadal dysgenesis without other symptoms. Human DMRT1 gene, which is located at 9p24.3, is expressed in testis and ovary and has been considered, among others, a candidate autosomal gene responsible for gonadal dysgenesis. In this report we describe a nucleotide insertion in DMRT1 3'UTR in a patient of XY partial gonadal dygenesis. The 3'UTR+11insT is located within a conserved motif important for mRNA stabilization.

A SRY-HMG box frame shift mutation inherited from a mosaic father with a mild form of testicular dysgenesis syndrome in Turner syndrome patient

BackgroundSex determining factor (SRY) located on the short arm of the Y chromosome, plays an important role in initiating male sex determination, resulting in development of testicular tissue. Presence of the SRY gene in females results in XY sex reversal and increased risk of gonadal germ cell tumours if the karyotype also includes the so-called GonadoBlastoma on the Y chromosome (GBY) region. The majority of mutations within the SRY gene are de novo affecting only a single individual in the family. The mutations within the high-mobility group (HMG) region have the potential to affect its DNA binding activity.Case PresentationWe performed G- and R-banding cytogenetic analysis of the patient and her family members including her father. We also performed molecular genetic analysis of SRY gene. Cytogenetic analysis in the patient (Turner Syndrome) revealed the mosaic karyotype as 45, X/46, XY (79%/21% respectively) while her father (milder features with testicular dysgenesis syndrome) has a normal male karyotype (46, XY). Using molecular approach, we screened the patient and her father for mutations in the SRY gene. Both patient and her father showed the same deletion of cytosine within HMG box resulting in frame shift mutation (L94fsX180), the father in a mosaic pattern. Histological examination of the gonads from the patient revealed the presence of gonadoblastoma formation, while the father presented with oligoasthenozoospermia and a testicular seminoma. The frameshift mutation at this codon is novel, and may result in a mutated SRY protein.ConclusionOur results suggest that lack of a second sex chromosome in majority cells of the patient may have triggered the short stature and primary infertility, and the mutated SRY protein may be associated with the development of gonadoblastoma. It is of importance to note that mosaic patients without a SRY mutation also have a risk for malignant germ cell tumors.

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.

No Differences in the Sry Gene between Males and XY Females in Akodon (Rodentia, Cricetidae)

Several species of the South American genus Akodon present fully fertile XY females besides XX ones. To analyze the possibility of a Sry mutation as the cause of sex reversal in A. azarae and A. boliviensis, we determined the sequence of the Sry gene in 2 males and 3 XY females from each of these species. The Sry gene sequence was also studied in A. dolores, a species that does not have XY females. In inter-specific comparisons, the percentage identities with respect to the region analyzed varied between 96.8% and 97.9%. An ORF of 543 nucleotides was identified, and the predicted Sry proteins comprised 180 amino acids, with an HMG domain of 83 amino acids. Our results indicate that female sex reversal in A. azarae and A. boliviensis cannot be explained by sequence differences in the Sry region analyzed here, which includes the complete ORF and, together with previous results concerning the inheritance of the XY condition, show that Sry mutation is not the basis of sex reversal.