Sex dimorphism of weight and length at birth: evidence based on disorders of sex development.

BACKGROUND: Males have higher weight and length at birth than females. AIM: To verify the influence of the Y chromosome and the action of intrauterine androgens on weight and length at birth of children with Disorders of Sex Development (DSD). SUBJECTS AND METHODS: A cross-sectional and retrospective study. Patients with Turner syndrome (TS), complete (XX and XY), mixed (45,X/46,XY) and partial (XY) gonadal dysgenesis (GD), complete (CAIS) and partial (PAIS) androgen insensitivity syndromes and XX and XY congenital adrenal hyperplasia (CAH) were included. Weight and length at birth were evaluated. RESULTS: Weight and length at birth were lower in TS and mixed GD when compared to XY and XX DSD cases. In turn, patients with increased androgen action (117 cases) had higher weight and length at birth when compared to those with absent (108 cases) and decreased (68 cases) production/action. In birthweight, there was a negative influence of the 45,X/46,XY karyotype and a positive influence of increased androgen and gestational age. In birth length, there was a negative influence of the 45,X and 45,X/46,XY karyotypes and also a positive influence of increased androgen and gestational age. CONCLUSIONS: The sex dimorphism of weight and length at birth could possibly be influenced by intrauterine androgenic action.

OCT4 immunohistochemistry may be necessary to identify the real risk of gonadal tumors in patients with Turner syndrome and Y chromosome sequences.

BACKGROUND: The aim of this study was to investigate the frequency of gonadal tumors among patients with Turner syndrome (TS) carrying Y-derivative sequences in their chromosomal constitution. METHODS: Six out of 260 patients with TS were selected based on mosaicism of the entire Y chromosome; 10 were included because Y-derivative sequences have been detected by PCR with specific oligonucleotides (sex-determining region on the Y, testis specific-protein, Y and DYZ3) and further confirmed by FISH. The 16 patients were subjected to bilateral gonadectomy at ages varying from 8.7 to 18.2 years. Both histopathological investigation with hematoxylin and eosin (H&E) and immunohistochemical analysis with anti-octamer-binding transcription factor 4 (OCT4) antibody were performed. RESULTS: Gonadal neoplasia was not detected in any of the 32 gonads evaluated by H&E; however, four gonads (12%) from three patients (19%) had positive OCT4 staining in 50-80% of nuclei, suggesting the existence of germ cell tumors (gonadoblastoma or in situ carcinoma). CONCLUSIONS: Evaluation of the real risk of development of gonadal tumors in TS patients with Y-derivative sequences in their chromosomal constitution may require a specific histopathological study, such as immunohistochemistry with OCT4.

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.

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.

Complete XY gonadal dysgenesis due to p.D293N homozygous mutation in the NR5A1 gene: a case study.

The SRY gene (sex-determining region on the Y chromosome; MIM *480000) is responsible for initiating male gonadal development. However, only 15-20% of the cases of XY gonadal dysgenesis are due to mutations in its sequence. Recently, heterozygous mutations in the NR5A1 gene (nuclear receptor subfamily 5, group A, member 1; MIM +184757) have been described in association with ovarian failure and disorders of testis development with or without adrenal failure. Here we describe a case of XY complete gonadal dysgenesis due to a p.D293N homozygous mutation in the NR5A1 gene, with normal SRY and no adrenal failure.

Effects of growth hormone on body proportions in Turner syndrome compared with non-treated patients and normal women.

BACKGROUND: The majority of anthropometric assessments in Turner syndrome (TS) patients has focused on height. AIM: To analyze body proportions in young adult TS patients either treated or not treated with rhGH, and to compare them with a group of age-matched healthy women. SUBJECTS AND METHODS: Standing height, sitting height, weight, foot and leg lengths, arm span, head circumference, biliac and biacromial diameters were measured in 52 non-treated TS patients, 30 treated with rhGH and 133 healthy women. RESULTS: Age at the start of rhGH therapy varied from 7.8 to 15.1 yr (10.0±1.3 yr), the duration of treatment from 2.8 to 8.2 yr (3.7±1.5 yr) and the mean recombinant human GH (rhGH) dose was 0.42 mg/kg/week (from 0.32 to 0.50 mg/kg/week). Nontreated patients did not show any difference in anthropometric variables when compared with the treated ones, except for hand length (p=0.02) and height (p=0.05), which were increased in the treated group. All anthropometric variables, except head circumference, were different when comparing TS patients (either treated or not) with age-matched healthy women. CONCLUSION: Brazilian TS patients either treated or not with rhGH showed almost no differences in terms of their body proportions. This result is probably due to the late age at the start of treatment, and/or the short period of rhGH administration. Hand length was different between the groups, showing the importance of including the extremities in body proportion assessment during rhGH treatment of TS patients.

Congenital perineal lipoma presenting as ambiguous genitalia.

BACKGROUND: Congenital perineal lipoma is extremely rare and may lead to a misdiagnosis of ambiguous genitalia. CASE REPORTS: We report on two girls referred to our service for ambiguous genitalia. Patient 1 (17 days old) and patient 2 (2 months old) had unremarkable gestational and perinatal histories. Both had normal female external genitalia and a 46,XX karyotype. Patient 1 had a polypoid, protruding 3.0 x 2.0 x 1.5-cm phallic-like mass arising at the inferior border of the left labium majora, and patient 2 had a similar mass of 1.5 x 1.5 x 1.0 cm at the same site and an imperforate anus. In both cases the mass was removed and found to be a lipoma. DISCUSSION: To our knowledge, perineal lipoma has been reported only in eleven girls, nine of them with associated anorectal malformation. Migration and fusion of the labioscrotal folds and formation of the urorectal septum are simultaneous developmental events occurring in the same region, which may explain the association of perineal lipoma and anorectal malformations.

Allelic frequencies of the 35delG mutation of the GJB2 gene in different Brazilian regions.

Mutations in the GJB2 gene, which encodes the protein connexin 26, are a major cause of autosomal recessive deafness. The most frequent mutation, 35delG, has a carrier frequency as high as 4% in some countries, and this frequency varies in different ethnic groups. Most of the Brazilian population results from interethnic crosses of people from three continents (European, African, and Amerindian), and the proportion of each varies according to the geographical region of the country. To verify if the different ethnic composition of Brazilian regions leads to variable 35delG carrier frequencies, we performed the screening of the 35delG mutation using DNA from dried-blood filter paper samples obtained from 1,856 newborns from 10 cities in different regions. The 35delG mutation was found in 25 individuals (1.35%), indicating an overall carrier frequency of 1:74. This frequency was 1:47 in the north, 1:64 in the southeast, 1:85 in the south and 1:124 in the northeast, but these differences were not significant. The overall frequency of the 35delG allele was estimated as 0.0067, and comparison between expected and observed genotype frequencies indicates that the population is in Hardy-Weinberg equilibrium.

Female counterpart of shawl scrotum in Aarskog-Scott syndrome.

Aarskog-Scott syndrome (ASS) is an X-linked disorder characterized by facial, skeletal and genital anomalies, including penoscrotal transposition in males. We report on a girl from a family with ASS who exhibits a transposition of the clitoris.

Female counterpart of shawl scrotum in aarskog-scott syndrome

Aarskog-Scott syndrome (ASS) is an X-linked disorder characterized by facial, skeletal and genital anomalies, including penoscrotal transposition in males. We report on a girl from a family with ASS who exhibits a transposition of the clitoris.

A rare case of aniridia and balanced translocation (5;11) (p15.3;q22) arising in the same subject: a challenge for genetic counseling.

The authors report on a case of isolated aniridia caused by haploinsufficiency of the PAX6 gene, which is located on 11p13, and a balanced translocation t(5;l1)(p15.3;q22) inherited respectively from his father and his mother. Due to the coincidence of two abnormalities in the same chromosome, the segregation of the mutant allele leading to aniridia and of the chromosomes involved in the translocation are not independent events. Considering that both monosomy and trisomy for 11q22-qter are unviable, his offspring may inherit either the PAX6 mutation or the balanced translocation. However, depending on the occurrence of crossing over, there is a possibility for him to have normal offspring; on the other hand, he may also father children with both anomalies. This unusual case, in which the proband has a presumably very low chance of completely normal offspring, turned to be a challenge for genetic counseling.

A naturally occurring deletion in the SRY promoter region affecting the Sp1 binding site is associated with sex reversal.

Male to female sex reversal results from failure of testis development. Mutations in the SRY gene or in other genes involved in the sexual differentiation pathway are considered to cause XY gonadal dysgenesis. The majority of the mutations in the SRY described so far are located within the SRY coding region, mainly in the HMG-box conserved domain. Comparison of 5' flanking SRY gene sequences among different species indicated the presence of several putative conserved consensus sequences for different transcription regulators. In this study, we investigated a 360 bp sequence encompassing the SRY putative core promoter, in 17 patients with variable degrees of 46,XY sex reversal, which have been previously shown not to bear mutations in the SRYcoding region. Sequencing analysis of the SRYpromoter in one patient with complete XY gonadal dysgenesis revealed a three base pair deletion in one of the Sp1 binding sites. The deletion abolished Sp1 binding in vitro. This is the first report on a naturally occurring mutation affecting the Sp1 regulatory element in the SRY promoter region, which is associated with sex reversal. Additionally, upon familial investigation the father, who had 18 genital surgeries due to severe hypospadia without cryptorchidism, was found to bear the same deletion and several relatives were referred to have sexual ambiguity.

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.

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.

Frequency of the 35delG mutation in the GJB2 gene in samples of European, Asian, and African Brazilians.

Mutations in the GJB2 gene are a major cause of congenital deafness. One specific mutation, the 35delG mutation, has accounted for most of the GJB2 mutations detected in European populations and is one of the most frequent disease mutations identified so far. We evaluated the frequency of the 35delG mutation in DNA samples from Brazilians of European, Asian, and African ancestry. All DNA samples were screened for the 35delG mutation using an allele-specific PCR. This study shows that the frequency of a common mutation (35delG) is significantly lower in non-European populations.

Novel mutations affecting SRY DNA-binding activity: the HMG box N65H associated with 46,XY pure gonadal dysgenesis and the familial non-HMG box R30I associated with variable phenotypes.

The SRY gene (sex-determining region of the Y chromosome) 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. We describe here two novel missense mutations in the SRY gene after the screening of 17 patients, including 3 siblings, with 46,XY gonadal dysgenesis and 4 true hermaphrodites. One of the mutations, an A to C transversion within the HMG box, causes the N65H substitution and it was found in a patient presenting 46,XY pure gonadal dysgenesis. The Escherichia coli expressed SRY(N65H) protein did not present DNA-binding activity in vitro. The other mutation, a G to T transversion, causes the R30I substitution. This mutation was found in affected and nonaffected members of a family, including the father, two siblings with partial gonadal dysgenesis, a phenotypic female with pure gonadal dysgenesis, and three nonaffected male siblings. The G to T base change was not found in the SRY sequence of 100 normal males screened by ASO-PCR. The R30I mutation is located upstream to the HMG box, within the (29)RRSSS(33) phosphorylation site. The E. coli expressed SRY(R30I) protein was poorly phosphorylated and consequently showed reduced DNA-binding capacity in vitro.

Deafness resulting from mutations in the GJB2 (connexin 26) gene in Brazilian patients.

Congenital deafness occurs in approximately 1 in 1000 live births. In developed countries about 60% of hearing loss is genetic. However, in Brazil most cases of hearing loss are due to environmental factors, such as congenital infections (mainly rubella), perinatal anoxia, kernicterus and meningitis. Recently, it has been demonstrated that the GJB2 gene is a major gene underlying congenital sensorial deafness. Mutations in this gene cause 10-20% of all genetic sensory hearing loss. One specific mutation, 35delG, accounts for the majority of mutant alleles. The extent of the hearing impairment varies from mild/moderate to profound, even within the patients homozygous for the common 35delG mutation. There may also be progression with age. Mutation analysis in the GJB2 gene was performed on 36 families (group A) presenting with at least one individual with non-syndromic deafness (NSD). An unselected series of 26 deaf individuals referred by other services where the environmental factors were not completely excluded was also part of the study (group B). Mutations in the GJB2 gene were found in 22% (eight patients) of the families tested in group A, and 11.5% (three patients) of individuals within group B. This finding should facilitate diagnosis of congenital deafness and allow early treatment of the affected subjects.

A boy with mental retardation, blepharophimosis and hypothyroidism: a diagnostic dilemma between Young-Simpson and Ohdo syndrome.

We report a male infant with an association of hypothyroidism and unusual facies, including blepharophimosis, which is similar to the dysmorphic features observed in the condition first described by Young and Simpson [(1987) J Med Genet 24:715-7161. On the other hand, the patient also shares many features with those reported as having Ohdo blepharophimosis syndrome [Ohdo et al, (1986) J Med Genet 23:242-244]. Previous case reports are reviewed and difficulties concerning the differential diagnosis of these conditions are discussed.

Evaluation of the tubular and interstitial functions of the testis in 46,XY patients with ambiguous genitalia.

Investigation of the origin of sexual ambiguity is complex. Although testicular function has traditionally been assessed only by examining the steroidogenic capacity of Leydig cells and spermatogenesis, it has recently been shown that the measurement of serum anti-Müllerian hormone (AMH) as a marker of Sertoli cell function may also help clinicians. The aim of this study was to evaluate both Leydig and Sertoli cell functions in 46,XY patients with intersex states in order to establish biochemical patterns that would help to reach an etiologic diagnosis. We measured serum androgens, AMH and gonadotropins in 24 patients with sexual ambiguity and XY karyotype: 8 with gonadal dysgenesis (GD), 3 with 3beta-hydroxysteroid dehydrogenase deficiency (3betaHSD), 5 with androgen insensitivity syndrome (AIS), 4 with 5alpha-reductase 2 (SRD5A2) deficiency, and 4 were of unknown origin or idiopathic. Our results showed that while testosterone was low and gonadotropins elevated in patients with either GD or 3betaHSD, AMH was low in the former and high in the latter. Serum AMH and gonadotropins were normal or high in patients with 3betaHSD or AIS, but these could be distinguished by testosterone levels. Serum testosterone and gonadotropins were normal or high in AIS and SRD5A2 deficiency patients; however, while AMH was elevated in AIS, it was not the case in SRD5A2 deficiency patients, indicating that testosterone is sufficient to inhibit AMH within the testis. In idiopathic cases gonadotropins and testosterone were normal, and AMH was normal or low. We conclude that the combined measurement of androgens, AMH and gonadotropins helps to establish the diagnosis in intersex patients.