New observations on minifascicular neuropathy with sex-dependent gonadal dysgenesis: a case series with nerve ultrasound assessment.

BACKGROUND: Gonadal dysgenesis with minifascicular neuropathy (GDMN) is a rare autosomal recessive condition associated with biallelic DHH pathogenic variants. In 46, XY individuals, this disorder is characterized by an association of minifascicular neuropathy (MFN) and gonadal dysgenesis, while in 46, XX subjects only the neuropathic phenotype is present. Very few patients with GDMN have been reported so far. We describe four patients with MFN due to a novel DHH likely pathogenic homozygous variant and the results of nerve ultrasound assessment. METHODS: This retrospective observational study included 4 individuals from 2 unrelated Brazilian families evaluated for severe peripheral neuropathy. Genetic diagnosis was performed with a peripheral neuropathy next-generation sequencing (NGS) panel based on whole exome sequencing focused analysis that included a control SRY probe to confirm genetic sex. Clinical characterization, nerve conduction velocity studies, and high-resolution ultrasound nerve evaluation were performed in all subjects. RESULTS: Molecular analysis disclosed in all subjects the homozygous DHH variant p.(Leu335Pro). Patients had a striking phenotype, with marked trophic changes of extremities, sensory ataxia, and distal anesthesia due to a sensory-motor demyelinating polyneuropathy. One 46, XY phenotypically female individual had gonadal dysgenesis. High-resolution nerve ultrasound showed typical minifascicular formation and increased nerve area in at least one of the nerves assessed in all patients. CONCLUSION: Gonadal dysgenesis with minifascicular neuropathy is a severe autosomal recessive neuropathy characterized by trophic alterations in limbs, sensory ataxia, and distal anesthesia. Nerve ultrasound studies are very suggestive of this condition and may help to avoid invasive nerve biopsies.

A Novel Look at Dosage-Sensitive Sex Locus Xp21.2 in a Case of 46,XY Partial Gonadal Dysgenesis without NR0B1 Duplication.

A region of 160 kb at Xp21.2 has been defined as dosage-sensitive sex reversal (DSS) and includes the NR0B1 gene, considered to be the candidate gene involved in XY gonadal dysgenesis if overexpressed. We describe a girl with 46,XY partial gonadal dysgenesis carrying a 297 kb duplication at Xp21.2 upstream of NR0B1 initially detected by chromosomal microarray analysis. Fine mapping of the breakpoints by whole-genome sequencing showed a tandem duplication of TASL (CXorf21), GK and partially TAB3, upstream of NR0B1. This is the first description of an Xp21.2 duplication upstream of NR0B1 associated with 46,XY partial gonadal dysgenesis.

A Small Supernumerary Xp Marker Chromosome Including Genes NR0B1 and MAGEB Causing Partial Gonadal Dysgenesis and Gonadoblastoma.

Copy number variations of several genes involved in the process of gonadal determination have been identified as a cause of 46,XY differences of sex development. We report a non-syndromic 14-year-old female patient who was referred with primary amenorrhea, absence of breast development, and atypical genitalia. Her karyotype was 47,XY,+mar/46,XY, and FISH analysis revealed the X chromosome origin of the marker chromosome. Array-CGH data identified a pathogenic 2.0-Mb gain of an Xp21.2 segment containing NR0B1/DAX1 and a 1.9-Mb variant of unknown significance from the Xp11.21p11.1 region. This is the first report of a chromosomal microarray analysis to reveal the genetic content of a small supernumerary marker chromosome detected in a 47,XY,+der(X)/46,XY karyotype in a non-syndromic girl with partial gonadal dysgenesis and gonadoblastoma. Our findings indicate that the mosaic presence of the small supernumerary Xp marker, encompassing the NR0B1/DAX1 gene, may have been the main cause of dysgenetic testes development, although the role of MAGEB and other genes mapped to the Xp21 segment could not be completely ruled out.

Gene dosage of DAX-1, determining in sexual differentiation: duplication of DAX-1 in two sisters with gonadal dysgenesis.

Two sisters phenotypically normal females, presenting with tumor abdominal mass with histopathological findings of teratoma and gonadoblastoma associated to 46,XY male-to-female sex reversal syndrome, secondary to a duplication in DAX-1, possibly inherited of maternal gonadal mosaicism. Copy number variation and functional effects of the duplication were done by MLPA multiplex ligation-dependent probe amplification and real time PCR. DAX-1, also known as dosage sensitive sex reversal gene (DSS), is considered the most likely candidate gene involved in XY gonadal dysgenesis when overexpressed. The excess of DAX-1 gene disturbs testicular development by down regulation of SF-1, WT1, and SOX9. This is the first report of 46,XY sex reversal in two siblings who have a maternally inherited duplication of DAX-1 associated with reduced levels of expression of downstream genes as SOX9-SF1.

NR5A1 Loss-of-Function Mutations Lead to 46,XY Partial Gonadal Dysgenesis Phenotype: Report of Three Novel Mutations.

Mutations in the NR5A1 gene, which encodes the steroidogenic factor 1 (SF1), are responsible for different phenotypes of disorders of sex development (DSD), such as bilateral anorchia and hypospadias. Furthermore, they can be associated with primary amenorrhea, premature ovarian failure, male infertility, adrenal tumors, and endometriosis. Direct sequencing of the 7 NR5A1 exons including ∼1,000 bp of the 5'-upstream and 3'-downstream regions and all intron-exon boundaries was performed in patients with DSD. Three different in silico tools were used to assess the consequences of a splice site mutation. As a result, 3 novel NR5A1 mutations were identified in 3 patients with 46,XY partial gonadal dysgenesis: p.Lys38* and p.Leu80Trpfs*8 lead to premature translation termination codons within the SF1 DNA-binding domain, and the intronic nucleotide substitution c.1138+1G>T at the intron 6 donor splice site is considered to modify correct splicing. We assume that the anomalous mRNA produced as a result of p.Lys38* and p.Leu80Trpfs*8 will be degraded by nonsense-mediated mRNA decay even before translation, leading to SF1 haploinsufficiency. The c.1138+1G>T mutation is expected to produce a truncated protein. Heterozygous SF1 loss-of-function mutations in these cases resulted in mild DSD manifestations, such as dysgenetic testes, spontaneous puberty, and preserved adrenal function.

A Cytogenomic Approach in a Case of Syndromic XY Gonadal Dysgenesis.

This is the first molecular characterization of a female XY patient with an Xp duplication due to an X;22 translocation. Array CGH detected a copy number gain of ∼36 Mb in the Xp22.33p21.1 region involving 150 genes. Clinical and molecular studies described in the literature have suggested DAX1 duplication as the major cause responsible for a sex reversal phenotype. Additionally, the interaction between genes and their possible role in clinical features are presented to support the discussion on genotype-phenotype correlation in cases of syndromic XY gonadal dysgenesis.

[The use of FISH on buccal smear to investigate mosaicism with a 45,X cell line: study on healthy men and patients with disorders of sex development]. / Uso da FISH em mucosa oral para investigação de mosaicismo com linhagem 45,X: estudo com homens saudáveis e pacientes com distúrbios da diferenciação do sexo.

OBJECTIVE: To verify whether fluorescence in situ hybridization (FISH) of cells from the buccal epithelium could be employed to detect cryptomosaicism with a 45,X lineage in 46,XY patients. SUBJECTS AND METHODS: Samples of nineteen 46,XY healthy young men and five patients with disorders of sex development (DSD), four 45,X/46,XY and one 46,XY were used. FISH analysis with X and Y specific probes on interphase nuclei from blood lymphocytes and buccal epithelium were analyzed to investigate the proportion of nuclei containing only the signal of the X chromosome. RESULTS: The frequency of nuclei containing only the X signal in the two tissues of healthy men did not differ (p = 0.69). In all patients with DSD this frequency was significantly higher, and there was no difference between the two tissues (p = 0.38), either. CONCLUSIONS: Investigation of mosaicism with a 45,X cell line in patients with 46,XY DSD or sterility can be done by FISH directly using cells from the buccal epithelium.

Absence of inactivating mutations and deletions in the DMRT1 and FGF9 genes in a large cohort of 46,XY patients with gonadal dysgenesis.

Despite advances in our understanding of the mechanisms involved in sex determination and differentiation, the specific roles of many genes in these processes are not completely understood in humans. Both DMRT1 and FGF9 are among this group of genes. Dmrt1 controls germ cell differentiation, proliferation, migration and pluripotency and Sertoli cell proliferation and differentiation. Fgf9 has been considered a critical factor in early testicular development and germ cell survival in mice. We screened for the presence of DMRT1 and FGF9 mutations in 33 patients with 46,XY gonadal dysgenesis. No deletions in either DMRT1 or FGF9 were identified using the MLPA technique. Eight allelic variants of DMRT1 were identified, and in silico analysis suggested that the novel c.968-15insTTCTCTCT variant and the c.774G>C (rs146975077) variant could have potentially deleterious effects on the DMRT1 protein. Nine previously described FGF9 allelic variants and six different alleles of the 3' UTR microsatellite were identified. However, none of these DMRT1 or FGF9 variants was associated with increased 46,XY gonadal dysgenesis. In conclusion, our study suggests that neither DMRT1 nor FGF9 abnormalities are frequently involved in dysgenetic male gonad development in patients with non-syndromic 46,XY disorder of sex development.

Clinical and molecular spectrum of patients with 17ß-hydroxysteroid dehydrogenase type 3 (17-ß-HSD3) deficiency.

The enzyme 17ß-hydroxysteroid dehydrogenase type 3 (17-ß-HSD3) catalyzes the conversion of androstenedione to testosterone in the testes, and its deficiency is a rare disorder of sex development in 46,XY individuals. It can lead to a wide range of phenotypic features, with variable hormonal profiles. We report four patients with the 46,XY karyotype and 17-ß-HSD3 deficiency, showing different degrees of genital ambiguity, increased androstenedione and decreased testosterone levels, and testosterone to androstenedione ratio < 0.8. In three of the patients, diagnosis was only determined due to the presence of signs of virilization at puberty. All patients had been raised as females, and female gender identity was maintained in all of them. Compound heterozygosis for c.277+2T>G novel mutation, and c.277+4A>T mutation, both located within the intron 3 splice donor site of the HSD17B3 gene, were identified in case 3. In addition, homozygosis for the missense p.Ala203Val, p.Gly289Ser, p.Arg80Gln mutations were found upon HSD17B3 gene sequencing in cases 1, 2, and 4, respectively.

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

OBJECTIVE: 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. DESIGN: Retrospective study based on data from all patients with CGD seen in our service from 1989 to 2010. SETTING: Clinic for disorders of sex development, University Hospital, State University of Campinas. PATIENT(S): 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. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): None. RESULT(S): 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. CONCLUSION(S): 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.

The novel p.E89K mutation in the SRY gene inhibits DNA binding and causes the 46,XY disorder of sex development.

Male sex determination in humans is controlled by the SRY gene, which encodes a transcriptional regulator containing a conserved high mobility group box domain (HMG-box) required for DNA binding. Mutations in the SRY HMG-box affect protein function, causing sex reversal phenotypes. In the present study, we describe a 19-year-old female presenting 46,XY karyotype with hypogonadism and primary amenorrhea that led to the diagnosis of 46,XY complete gonadal dysgenesis. The novel p.E89K missense mutation in the SRY HMG-box was identified as a de novo mutation. Electrophoretic mobility shift assays showed that p.E89K almost completely abolished SRY DNA-binding activity, suggesting that it is the cause of SRY function impairment. In addition, we report the occurrence of the p.G95R mutation in a 46,XY female with complete gonadal dysgenesis. According to the three-dimensional structure of the human SRY HMG-box, the substitution of the conserved glutamic acid residue by the basic lysine at position 89 introduces an extra positive charge adjacent to and between the positively charged residues R86 and K92, important for stabilizing the HMG-box helix 2 with DNA. Thus, we propose that an electrostatic repulsion caused by the proximity of these positive charges could destabilize the tip of helix 2, abrogating DNA interaction.

46,XY and 45,X/46,XY testicular dysgenesis: similar gonadal and genital phenotype, different prognosis.

The objective of this study was to describe the change in diagnosis and prognosis of a child with testicular dysgenesis and 46,XY karyotype after detection of a 45,X cell line and to discuss the difficulties caused by the terms mixed gonadal dysgenesis (MGD) and XY partial gonadal dysgenesis (XYPGD). One case was reported including clinical and laboratory findings of a child of 41-day-old infant with 1.3-cm phallus, penoscrotal hypospadias and left prepubertal testis. Karyotype 46,XY (16 cells), normal hormone levels. Right streak gonad, epididymis and müllerian remnants were removed; initial diagnosis was XYPGD. Persistent growth retardation led to further cytogenetic analysis (50 cells) and detection of a 45,X cell line. Detection of a 45,X lineage changed both the diagnosis to MGD and also the prognosis.The number of cells analyzed in karyotyping is critical. Use of MGD and XYPGD to designate both a histological picture and a syndromic diagnosis, results in lack of emphasis on clinical differences between 46,XY and 45,X/46,XY subjects.

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.

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.

Male infertility related to an aberrant karyotype, 46,XY,9ph,9qh+.

OBJECTIVE: To report a man with primary infertility and variant karyotype. DESIGN: Case report. SETTING: Private practice. PATIENT(S): A 37-year-old man with 4 years of primary infertility due to oligoasthenozoospermia. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): G- and C-banding. Polymerase chain reaction for SRY, DBY, RBMY, DAZ, AMELX, and AMELY. RESULT(S): G-band analysis of the proband revealed a 46,XY,9ph,9qh+ karyotype. C-banding confirmed increase in the heterochromatin in one chromosome 9 and inversion in the other. CONCLUSION(S): The morphologic difference between the homologous chromosomes 9 may have been responsible for an error in crossing-over, leading to aberrant spermatozoa and consequently to infertility.

XX Maleness and XX true hermaphroditism in SRY-negative monozygotic twins: additional evidence for a common origin.

CONTEXT: Differentiation of testicular tissue in 46,XX individuals is seen either in XX males, the majority of them with SRY gene, or in individuals, usually SRY(-), with ovotesticular disorder of sex development (OT-DSD). Although they are sporadic cases, there are some reports on familial recurrence, including coexistence of XX maleness and OT-DSD in the same family. OBJECTIVE: We report on a case of SRY(-) 46,XX monozygotic twins with genital ambiguity. METHODS: Hormonal evaluation included testosterone, FSH, and LH measurements. SRY gene was investigated by PCR and two-step PCR in peripheral leukocytes and gonadal tissues, respectively. Direct DNA sequencing of the DAX-1 coding sequence was performed. Real-time PCR for SOX9 region on chromosome 17 was obtained. RESULTS: Both twins had a 46,XX karyotype. Twin A had a 1-cm phallus with chordee, penoscrotal hypospadias, and palpable gonads. Serum levels of FSH (2.34 mIU/ml), LH (8.8 mIU/ml), and testosterone (1.6 ng/ml) were normal, and biopsies revealed bilateral testes. Twin B had a 0.5-cm phallus, perineal hypospadias, no palpable gonad on the right, and a left inguinal hernia. Hormonal evaluation revealed high FSH (8.2 mIU/ml) and LH (15 mIU/ml) and low testosterone (0.12 ng/ml). Upon herniotomy, a right testis (crossed ectopia) and a small left ovotestis were found. SRY gene was absent in both peripheral leukocytes and gonadal tissue samples. Neither DAX-1 mutations nor SOX9 duplication was identified. CONCLUSIONS: This case provides evidence that both XX maleness and XX OT-DSD are different manifestations of the same disorder of gonadal development.

Predictive value of anatomical findings and karyotype analysis in the diagnosis of patients with disorders of sexual development.

We assessed the predictive value of anatomical findings and karyotype for establishing a diagnostic orientation in patients with disorders of sex development (DSD). We performed a retrospective chart analysis of 228 patients, grouped into 4 categories: 46,XX DSD, non-dysgenetic testicular DSD, dysgenetic testicular DSD and ovotesticular DSD. Degree of virilisation, presence of vagina, presence of palpable gonads, size of gonads and a plain karyotype was available for all cases. 46,XX DSD due to congenital adrenal hyperplasia counted for 59.2% of the cases, non-dysgenetic testicular DSD for 13.6%, dysgenetic testicular DSD for 21.5% and ovotesticular DSD for 5.7%. Excluding congenital adrenal hyperplasia (CAH), a karyotype with at least one 46,XX cell line had a high diagnostic efficiency for ovotesticular DSD. In these patients, anatomical findings were not as useful to predict the gonadal phenotype. The existence of a 45,X cell line predicted with very high efficiency dysgenetic testicular DSD. Genital palpation was only partially helpful to predict the existence of testicular tissue. Non-dysgenetic testicular DSD could be ruled out with high efficiency in patients with an abnormal karyotype. Anatomical findings were helpful in 46,XY patients: palpated masses predicted non-dysgenetic testes with high accuracy. In all cases assessment of gonadal volume was less useful.

Frasier syndrome comes full circle: genetic studies performed in an original patient.

Frasier syndrome is a relatively rare disorder associated with XY gonadal dysgenesis, gonadoblastoma, and kidney failure. In this report, we identify a classic mutation in the Wilms' tumor 1 gene in one of the original cases of Frasier syndrome reported in this Journal in 1964.

Mutations in SRY and WT1 genes required for gonadal development are not responsible for XY partial gonadal dysgenesis.

The WT1 transcription factor regulates SRY expression during the initial steps of the sex determination process in humans, activating a gene cascade leading to testis differentiation. In addition to causing Wilms' tumor, mutations in WT1 are often responsible for urogenital defects in men, while SRY mutations are mainly related to 46,XY pure gonadal dysgenesis. In order to evaluate their role in abnormal testicular organogenesis, we screened for SRY and WT1 gene mutations in 10 children with XY partial gonadal dysgenesis, 2 of whom with a history of Wilms' tumor. The open reading frame and 360 bp of the 5' flanking sequence of the SRY gene, and the ten exons and intron boundaries of the WT1 gene were amplified by PCR of genomic DNA. Single-strand conformation polymorphism was initially used for WT1 mutation screening. Since shifts in fragment migration were only observed for intron/exon 4, the ten WT1 exons from all patients were sequenced manually. No mutations were detected in the SRY 5' untranslated region or within SRY open-reading frame sequences. WT1 sequencing revealed one missense mutation (D396N) in the ninth exon of a patient who also had Wilms' tumor. In addition, two silent point mutations were found in the first exon including one described here for the first time. Some non-coding sequence variations were detected, representing one new (IVS4+85A>G) and two already described (-7ATG T>G, IVS9-49 T>C) single nucleotide polymorphisms. Therefore, mutations in two major genes required for gonadal development, SRY and WT1, are not responsible for XY partial gonadal dysgenesis.

A de novo phe671eu mutation in the SRY gene in a patient with complete 46,XY gonadal dysgenesis.

The sex-determining region of the Y chromosome (SRY) gene initiates the process of male sex differentiation in mammalians. In humans, mutations in the SRY gene have been reported to account for 10-15% of the XY sex reversal cases. In this report we describe the clinical, endocrinological and molecular data of a patient with complete 46,XY gonadal dysgenesis caused by a de novo mutation affecting SRY amino acid phenylalanine at position 67 (F67L), located within the highly conserved high mobility group (HMG) box coding region of the gene.