Clinical and Laboratorial Features That May Differentiate 46,XY DSD due to Partial Androgen Insensitivity and 5α-Reductase Type 2 Deficiency

A case of mild partial androgen insensitivity syndrome in a juvenile boy

Androgen insensitivity syndrome (AIS) is a rare disorder with X-linked recessive inheritance in 46 XY patients. The clinical manifestations vary between patients, especially regarding external genitalia development. Herein, the case of AIS in a 13-year-old male, who was born with hypospadias and presented to the hospital with gynaecomastia that had developed from 8 years of age, is reported. No micropenis, cryptorchidism or bifid scrotum were found. Testis volume was 12 ml on both sides. His testosterone and luteinizing hormone levels were normal compared with sex- and age-adjusted reference range. His bone age was approximately 13 years according to Greulich-Pyle assessment. Sequence analysis of the androgen receptor (AR) gene revealed a mutation (c.2041A>G) in exon 4, a novel mutation site in the AR gene. Prediction analysis suggested this to be a disease-causing variant. A milder clinical presentation and normal hormone levels in cases of partial AIS might differ from the usually reported signs and symptoms. A diagnosis of AIS should not be ignored in teenage patients who present with gynaecomastia and hypospadias, but normal hormone levels.

Management of 46,XY Differences/Disorders of Sex Development (DSD) Throughout Life

Differences/disorders of sex development (DSD) are a heterogeneous group of congenital conditions that result in discordance between an individual's sex chromosomes, gonads, and/or anatomic sex. Advances in the clinical care of patients and families affected by 46,XY DSD have been achieved since publication of the original Consensus meeting in 2006. The aims of this paper are to review what is known about morbidity and mortality, diagnostic tools and timing, sex of rearing, endocrine and surgical treatment, fertility and sexual function, and quality of life in people with 46,XY DSD. The role for interdisciplinary health care teams, importance of establishing a molecular diagnosis, and need for research collaborations using patient registries to better understand long-term outcomes of specific medical and surgical interventions are acknowledged and accepted. Topics that require further study include prevalence and incidence, understanding morbidity and mortality as these relate to specific etiologies underlying 46,XY DSD, appropriate and optimal options for genitoplasty, long-term quality of life, sexual function, involvement with intimate partners, and optimizing fertility potential.

Growth Pattern in Chinese Children With 5α-Reductase Type 2 Deficiency: A Retrospective Multicenter Study

BACKGROUND

5α-reductase type 2 deficiency (5αRD) is an autosomal recessive hereditary disease of the group of 46, XY disorders of sex development (DSD).

OBJECTIVE

To study the growth pattern in Chinese pediatric patients with 5αRD.

SUBJECTS

Data were obtained from 141 patients with 5αRD (age: 0-16 years old) who visited eight pediatric endocrine centers from January 2010 to December 2017.

METHODS

In this retrospective cohort study, height, weight, and other relevant data were collected from the multicenter hospital registration database. Baseline luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), and dihydrotestosterone (DHT) after human chorionic gonadotropin (HCG) stimulation test were measured by enzyme enhanced chemiluminescence assay. Bone age (BA) was assessed using the Greulich-Pyle (G-P) atlas. Growth curve was constructed based on λ-median-coefficient of variation method (LMS).

RESULTS

The height standard deviation scores (HtSDS) and weight standard deviation scores (WtSDS) in 5αRD children were in the normal range as compared to normal boys. Significantly higher HtSDS was observed in patients with 5αRD who were <1 year old (t = 3.658, 2.103, P = 0.002, 0.048, respectively), and higher WtSDS in those <6 months old (t = 2.756, P = 0.012). Then HtSDS and WtSDS decreased gradually and fluctuated near the median of the same age until 13 years. WtSDS in 5αRD children from northern China were significantly higher than those from the south (Z = -2.670, P = 0.008). The variation tendency of HtSDS in Chinese 5αRDs was consistent with the trend of stimulating T. HtSDS and stimulating T in the external masculinization score (EMS) <7 group were slightly higher than those in EMS ≥ 7 group without significant difference. Additionally, the ratio of BA over chronological age (BA/CA) was significantly <1 in children with 5αRD.

CONCLUSION

Children with 5αRD had a special growth pattern that was affected by high levels of T, while DHT played a very small role in it. Their growth accelerated at age <1 year, followed by slowing growth and fluctuating height near normal median boys' height. The BA was delayed in 5αRD children. Androgen treatment, which may be considered anyway for male 5αRD patients with a micropenis, may also be beneficial for growth.

Large divergence in testosterone concentrations between men and women: Frame of reference for elite athletes in sex-specific competition in sports, a narrative review

OBJECTIVE

The purpose of this narrative review was to summarize available data on testosterone levels in normal, healthy adult males and females, to provide a physiologic reference framework to evaluate testosterone levels reported in males and females with conditions that elevate androgens, such as disorders of sex development (DSD), and to determine the separation or overlap of testosterone levels between normal and affected males and females.

METHODS

A literature review was conducted for published papers, from peer reviewed journals, reporting testosterone levels in healthy males and females, males with 46XY DSD, and females with hyperandrogenism due to polycystic ovary syndrome (PCOS). Papers were selected that had adequate characterization of participants, and description of the methodology for measurement of serum testosterone and reporting of results.

RESULTS

In the healthy, normal males and females, there was a clear bimodal distribution of testosterone levels, with the lower end of the male range being four- to fivefold higher than the upper end of the female range(males 8.8-30.9 nmol/L, females 0.4-2.0 nmol/L). Individuals with 46XY DSD, specifically those with 5-alpha reductase deficiency, type 2 and androgen insensitivity syndrome testosterone levels that were within normal male range. Females with PCOS or congenital adrenal hyperplasia were above the normal female range but still below the normal male range.

CONCLUSIONS

Existing studies strongly support a bimodal distribution of serum testosterone levels in females compared to males. These data should be considered in the discussion of female competition eligibility in individuals with possible DSD or hyperandrogenism.

Comparison between two inhibin B ELISA assays in 46,XY testicular disorders of sex development (DSD) with normal testosterone secretion

BACKGROUND

Inhibin B is a hormone produced by the Sertoli cells that can provide important information for the investigation of disorders of sex development (DSD) with 46,XY karyotype. The aim of this study is to compare two enzyme-linked immunosorbent assay (ELISA) assays for dosage of serum inhibin B in patients with 46,XY DSD with normal testosterone secretion.

METHODS

Twenty-nine patients with 46,XY DSD and normal testosterone secretion (partial androgen insensitivity syndrome [PAIS] [n=8]; 5α-reductase deficiency [n=7] and idiopathic 46,XY DSD [n=14]) were included. Molecular analysis of the AR and SRD5A2 genes were performed in all patients and the NR5A1 gene analysis in the idiopathic group. Measurements of inhibin B were performed by two second-generation ELISA assays (Beckman-Coulter and AnshLabs). Assays were compared using the interclass correlation coefficient (ICC) and the Bland-Altman method.

RESULTS

ICC was 0.915 [95% confidence interval (CI): 0.828-0.959], however, a discrepancy was observed between trials, which is more evident among higher values when analyzed by the Bland-Altman method.

CONCLUSIONS

It is recommended to perform the inhibin B measurement always using the same ELISA kit when several evaluations are required for a specific patient.

Partial androgen insensitivity syndrome due to somatic mosaicism of the androgen receptor

BACKGROUND

Androgen insensitivity syndrome (AIS) is the most frequent etiology of 46,XY disorders of sex development (DSDs), and it is an X-linked disorder caused by mutations in the androgen receptor (AR) gene. AIS patients present a broad phenotypic spectrum and individuals with a partial phenotype present with different degrees of undervirilized external genitalia. There are more than 500 different AR gene allelic variants reported to be linked to AIS, but the presence of somatic mosaicisms has been rarely identified. In the presence of a wild-type AR gene, a significant degree of spontaneous virilization at puberty can be observed, and it could influence the gender assignment, genetic counseling and the clinical and psychological management of these patients and the psychosexual outcomes of these patients are not known.

CASE PRESENTATION

In this study, we report two patients with AR allelic variants in heterozygous (c.382G>T and c.1769-1G>C) causing a partial AIS (PAIS) phenotype. The first patient was raised as female and she had undergone a gonadectomy at puberty. In both patients there was congruency between gender of rearing and gender identity and gender role.

CONCLUSIONS

Somatic mosaicism is rare in AIS and nonsense AR variant allelic can cause partial AIS phenotype in this situation. Despite the risk of virilization and prenatal androgen exposure, the gender identity and gender role was concordant with sex of rearing in both cases. A better testosterone response can be expected in male individuals and this should be considered in the clinical management.

A study of splicing mutations in disorders of sex development

The presence of splicing sequence variants in genes responsible for sex development in humans may compromise correct biosynthesis of proteins involved in the normal development of gonads and external genitalia. In a cohort of Brazilian patients, we identified mutations in HSD17B3 and SRD5A2 which are both required for human sexual differentiation. A number of these mutations occurred within regions potentially critical for splicing regulation. Minigenes were used to validate the functional effect of mutations in both genes. We evaluated the c.277 + 2 T > G mutation in HSD17B3, and the c.544 G > A, c.548-44 T > G and c.278delG mutations in SRD5A2. We demonstrated that these mutations altered the splicing pattern of these genes. In a genomic era these results illustrate, and remind us, that sequence variants within exon-intron boundaries, which are primarily identified for diagnostic purposes and have unknown pathogenicity, need to be assessed with regards to their impact not only on protein expression, but also on mRNA splicing.

Reprint of "Steroid 5α-reductase 2 deficiency"

Dihydrotestosterone is a potent androgen metabolite formed from testosterone by action of 5α-reductase isoenzymes. Mutations in the type 2 isoenzyme cause a disorder of 46,XY sex development, termed 5α-reductase type 2 deficiency and that was described forty years ago. Many mutations in the encoding gene have been reported in different ethnic groups. In affected 46,XY individuals, female external genitalia are common, but Mullerian ducts regress, and the internal urogenital tract is male. Most affected males are raised as females, but virilization occurs at puberty, and male social sex develops thereafter with high frequency. Fertility can be achieved in some affected males with assisted reproduction techniques, and adults with male social sex report a more satisfactory sex life and quality of life as compared to affected individuals with female social sex.

Steroid 5α-reductase 2 deficiency

Dihydrotestosterone is a potent androgen metabolite formed from testosterone by action of 5α-reductase isoenzymes. Mutations in the type 2 isoenzyme cause a disorder of 46,XY sex development, termed 5α-reductase type 2 deficiency and that was described forty years ago. Many mutations in the encoding gene have been reported in different ethnic groups. In affected 46,XY individuals, female external genitalia are common, but Mullerian ducts regress, and the internal urogenital tract is male. Most affected males are raised as females, but virilization occurs at puberty, and male social sex develops thereafter with high frequency. Fertility can be achieved in some affected males with assisted reproduction techniques, and adults with male social sex report a more satisfactory sex life and quality of life as compared to affected individuals with female social sex.

Retracted: Aetiology and clinical profile of children with 46, XY differences of sex development at an Indian referral centre

Retraction: 'Aetiology and clinical profile of children with 46, XY differences of sex development at an Indian referral centre' by Vasundhera Chauhan, Rima Dada, Vandana Jain The above article, published online on 8 August 2016 in Wiley Online Library (http://wileyonlinelibrary.com), has been retracted by agreement between the authors, the Journal Editors-in-Chief, Wolf-Bernhard Schill and Ralf Henkel, and Blackwell Verlag GmbH. The retraction has been agreed as the result of an unresolved dispute between the first author and a colleague research fellow due to the inclusion of data from patients who were simultaneously enrolled in two studies being conducted separately by the two parties. Reference Chauhan, V., Dada, R. and Jain, V. (2016), Aetiology and clinical profile of children with 46, XY differences of sex development at an Indian referral centre. Andrologia. doi:10.1111/and.12663.

408 Cases of Genital Ambiguity Followed by Single Multidisciplinary Team during 23 Years: Etiologic Diagnosis and Sex of Rearing

Objective. To evaluate diagnosis, age of referral, karyotype, and sex of rearing of cases with disorders of sex development (DSD) with ambiguous genitalia. Methods. Retrospective study during 23 years at outpatient clinic of a referral center. Results. There were 408 cases; 250 (61.3%) were 46,XY and 124 (30.4%) 46,XX and 34 (8.3%) had sex chromosomes abnormalities. 189 (46.3%) had 46,XY testicular DSD, 105 (25.7%) 46,XX ovarian DSD, 95 (23.3%) disorders of gonadal development (DGD), and 19 (4.7%) complex malformations. The main etiology of 46,XX ovarian DSD was salt-wasting 21-hydroxylase deficiency. In 46,XX and 46,XY groups, other malformations were observed. In the DGD group, 46,XY partial gonadal dysgenesis, mixed gonadal dysgenesis, and ovotesticular DSD were more frequent. Low birth weight was observed in 42 cases of idiopathic 46,XY testicular DSD. The average age at diagnosis was 31.7 months. The final sex of rearing was male in 238 cases and female in 170. Only 6.6% (27 cases) needed sex reassignment. Conclusions. In this large DSD sample with ambiguous genitalia, the 46,XY karyotype was the most frequent; in turn, congenital adrenal hyperplasia was the most frequent etiology. Malformations associated with DSD were common in all groups and low birth weight was associated with idiopathic 46,XY testicular DSD.

NR5A1 gene mutations: clinical, endocrine and genetic features in two girls with 46,XY disorder of sex development

BACKGROUND

Steroidogenic factor 1, encoded by the NR5A1 gene, is a key regulator of endocrine function within the hypothalamic-pituitary-steroidogenic axis. Both homozygous, compound heterozygous and heterozygous mutations in the NR5A1 gene may determine 46,XY disorders of sex development (DSD).

PATIENTS AND METHODS

NR5A1 gene sequencing was performed in a cohort of 6 patients with 46,XY DSD without specific diagnosis.

RESULTS

Heterozygous NR5A1 gene mutations were found in 2 girls, aged 0.5 years and 14 years. The older girl harbored the c.250C>T transition in exon 4 (p.Arg84Cys), previously reported in a Japanese girl. The younger girl presented a de novo novel exon 6 heterozygous frameshift mutation (c.1074dupG) in codon 359 associated with the p.Gly146Ala polymorphism the latter inherited from her father. This baby showed severe impairment of androgen secretion from the first months of life. Overt adrenal insufficiency did not occur, but the older girl showed subnormal cortisol peak after ACTH stimulation.

CONCLUSIONS

NR5A1 gene mutations are a relatively frequent cause of 46,XY DSD in humans. Clear indications for management of these individuals remain elusive, mainly when diagnosis is made in infancy. Long-term monitoring of adrenal function should be recommended.

Low frequency of androgen receptor gene mutations in 46 XY DSD, and fetal growth restriction

OBJECTIVE

The diagnosis of partial androgen insensitivity syndrome (PAIS) should be reserved for infants with a pathogenic androgen receptor gene (AR) mutation. However, only about 20% of infants with a clinical phenotype akin to PAIS have an AR mutation. We aimed to identify clinical features associated with the presence of an AR mutation.

METHODS

The external masculinisation score (EMS; normal=12), birth weight (BW), gestational age and BW SD score (BW-SDS) of 164 infants with a 'PAIS-like' phenotype were analysed in the Cambridge Disorders of Sex Development (DSD) Database, of whom 128 (78%) had no AR mutation ('AR mutation-negative') and 36 (22%) had an AR mutation ('AR mutation-positive').

RESULTS

The EMS was similar in AR mutation-negative and AR mutation-positive infants (median, IQR: 5.0, 3.0 to 6.0 vs 4.8, 3.0 to 6.0; p=0.33). AR mutation-negative infants had lower BW (2.33, 1.38 to 3.20 vs 3.18, 2.87 to 3.61 kg; p<0.001), lower gestational age (37.0, 34.0 to 40.0 vs 40.0, 39.0 to 40.0 weeks; p<0.001), and lower BW-SDS (-1.31, -2.33 to -0.46 vs -0.57, -1.19 to 0.33; p=0.001) compared to AR mutation-positive infants. More AR mutation-negative infants (47/128; 37%) than AR mutation-positive infants (2/36; 6%) had BW-SDS <-2 (p<0.001).

CONCLUSIONS

The severity of genital anomalies in this large cohort of infants with a 'PAIS-like' phenotype did not differentiate their AR status. Almost all the infants born small-for-gestational-age do not have an AR mutation. A category of 'XY DSD and fetal growth restriction, as yet unexplained' should be recognised.

The novel p.Cys65Tyr mutation in NR5A1 gene in three 46,XY siblings with normal testosterone levels and their mother with primary ovarian insufficiency

Background

Disorders of sex development (DSD) is the term used for congenital conditions in which development of chromosomal, gonadal, or phenotypic sex is atypical. Nuclear receptor subfamily 5, group A, member 1 gene (NR5A1) encodes steroidogenic factor 1 (SF1), a transcription factor that is involved in gonadal development and regulates adrenal steroidogenesis. Mutations in the NR5A1 gene may lead to different 46,XX or 46,XY DSD phenotypes with or without adrenal failure. We report a Brazilian family with a novel NR5A1 mutation causing ambiguous genitalia in 46,XY affected individuals without Müllerian derivatives and apparently normal Leydig function after birth and at puberty, respectively. Their mother, who is also heterozygous for the mutation, presents evidence of primary ovarian insufficiency.

Case presentation

Three siblings with 46,XY DSD, ambiguous genitalia and normal testosterone production were included in the study. Molecular analyses for AR, SRD5A2 genes did not reveal any mutation. However, NR5A2 sequence analysis indicated that all three siblings were heterozygous for the p.Cys65Tyr mutation which was inherited from their mother. In silico analysis was carried out to elucidate the role of the amino acid change on the protein function. After the mutation was identified, all sibs and the mother had been reevaluated. Basal hormone concentrations were normal except that ACTH levels were slightly elevated. After 1 mcg ACTH stimulation test, only the older sib showed subnormal cortisol response.

Conclusion

The p.Cys65Tyr mutation located within the second zinc finger of DNA binding domain was considered deleterious upon analysis with predictive algorithms. The identification of heterozygous individuals with this novel mutation may bring additional knowledge on structural modifications that may influence NR5A1 DNA-binding ability, and may also contribute to genotype-phenotype correlations in DSD. The slightly elevated ACTH basal levels in all three patients with 46,XY DSD and the subnormal cortisol response after 1 mcg ACTH stimulation in the older sib indicate that a long-term follow-up for adrenal function is important for these patients. Our data reinforce that NR5A1 analysis must also be performed in 46,XY DSD patients with normal testosterone levels without AR mutations.

Androgen insensitivity syndrome

Androgen insensitivity syndrome in its complete form is a disorder of hormone resistance characterised by a female phenotype in an individual with an XY karyotype and testes producing age-appropriate normal concentrations of androgens. Pathogenesis is the result of mutations in the X-linked androgen receptor gene, which encodes for the ligand-activated androgen receptor--a transcription factor and member of the nuclear receptor superfamily. This Seminar describes the clinical manifestations of androgen insensitivity syndrome from infancy to adulthood, reviews the mechanism of androgen action, and shows examples of how mutations of the androgen receptor gene cause the syndrome. Management of androgen insensitivity syndrome should be undertaken by a multidisciplinary team and include gonadectomy to avoid gonad tumours in later life, appropriate sex-hormone replacement at puberty and beyond, and an emphasis on openness in disclosure.