No correlation between androgen receptor CAG and GGN repeat length and the degree of genital virilization in females with 21-hydroxylase deficiency

Nonvirilized Genitalia in 3 Female Newborns With the Salt-Wasting Congenital Adrenal Hyperplasia Phenotype

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, a form of primary adrenal insufficiency characterized by impaired cortisol secretion and elevated androgen production, is the leading cause of atypical genitalia in the female newborn. Females with classic CAH, either salt-wasting or simple-virilizing form, usually present at birth with atypical genitalia ranging from clitoromegaly to male-appearing genitalia, due to in utero to elevated androgens (androstenedione and testosterone). Females with mild nonclassic CAH usually present with typical genitalia. Proving the importance of always keeping an open mind for exceptions to the rule, we report on 3 female newborns who presented with the nonvirilized genitalia, salt-wasting CAH phenotype and genotype most consistent with simple-virilizing CAH. It is only through a positive newborn screen identifying the females with CAH that they were diagnosed before developing adrenal and/or salt-wasting crisis.

Translating genomics to the clinical diagnosis of disorders/differences of sex development

The medical and psychosocial challenges faced by patients living with Disorders/Differences of Sex Development (DSD) and their families can be alleviated by a rapid and accurate diagnostic process. Clinical diagnosis of DSD is limited by a lack of standardization of anatomical and endocrine phenotyping and genetic testing, as well as poor genotype/phenotype correlation. Historically, DSD genes have been identified through positional cloning of disease-associated variants segregating in families and validation of candidates in animal and in vitro modeling of variant pathogenicity. Owing to the complexity of conditions grouped under DSD, genome-wide scanning methods are better suited for identifying disease causing gene variant(s) and providing a clinical diagnosis. Here, we review a number of established genomic tools (karyotyping, chromosomal microarrays and exome sequencing) used in clinic for DSD diagnosis, as well as emerging genomic technologies such as whole-genome (short-read) sequencing, long-read sequencing, and optical mapping used for novel DSD gene discovery. These, together with gene expression and epigenetic studies can potentiate the clinical diagnosis of DSD diagnostic rates and enhance the outcomes for patients and families.

Linking the degree of virilization in females with congenital adrenal hyperplasia to genotype

Mutations of CYP21A2 variably decrease 21-hydroxylase activity and result in a spectrum of disease expressions in patients with congenital adrenal hyperplasia (CAH). We examined the association between CYP21A2 mutations and virilization (Prader score) in females with CAH. The study population included 187 CAH females with fully characterized CYP21A2 mutations. One hundred fifty-eight patients were sorted into groups by expected enzyme activity (percent of normal activity) of the less severely affected allele: (A) null, 0%; (B) I2G, 1%; (C) I172N, 2%; and (D) V281L, >2%. We observed an inverse relationship between virilization and residual enzyme activity (P < 0.001). Subjects in group A or B had a significantly higher likelihood (unadjusted odds ratio: 16; P < 0.001) of developing severe virilization compared with those in group C. Surprisingly, 24% of group D patients, whose mutation is usually associated with nonclassical (NC) CAH, had severe virilization. Among subjects with the NC P30L mutation, 66% expressed unexpected virilization. Virilization, usually leading to extensive reconstructive surgery, is highly likely in patients with null or I2G mutations; however, NC mutations (P30L/V281L) may also lead to unexpected virilization. These findings have implications for prenatal counseling and highlight the need for additional investigations into other factors that influence virilization in CAH.

A Single Nucleotide Variant in the Promoter Region of 17β-HSD Type 5 Gene Influences External Genitalia Virilization in Females with 21-Hydroxylase Deficiency

BACKGROUND

In 21-hydroxylase deficiency (21-OHD), there is an influence of genotype on the severity of external genitalia virilization. However, females carrying mutations predicting a similar impairment of enzymatic activity present a wide variability of genital phenotypes. In such cases, interindividual variability in genes related to the sex steroid hormone pathway could play a role.

OBJECTIVE

To evaluate the influence of POR, HSD17B5 and SRD5A2 variants on the severity of external genitalia virilization in 21-OHD females.

DESIGN AND PATIENTS

Prader stages were evaluated in 178 females with 21-OHD from a multicenter study. The 21-OHD genotypes were divided into two groups according to their severity: severe and moderate. The influences of the POR p.A503V, HSD17B5 c.-71A>G, HSD17B5 c.-210A>C, and SRD5A2 p.A49T and p.V89L variants on the degree of external genitalia virilization were analyzed.

RESULTS

The POR p.A503V, HSD17B5 c.-71A>G, HSD17B5 c.-210A>C, and SRD5A2 p.A49T and p.V89L variants were found in 25, 33, 17, 1, and 31% of the alleles, respectively. In uni- and multilinear regression, HSD17B5 c.-210A>C has a significant influence on the degree of external genitalia virilization. This variant was also identified with a higher frequency in the most severely virilized females.

CONCLUSION

We demonstrated that a variant in the promoter region of HSD17B5 related to fetal androgen synthesis influences the genital phenotype in 21-OHD females.

Molecular CYP21A2 diagnosis in 480 Brazilian patients with congenital adrenal hyperplasia before newborn screening introduction

BACKGROUND

Most congenital adrenal hyperplasia (CAH) patients carry CYP21A2 mutations derived from conversion events involving the pseudogene, and the remaining carry new mutations.

OBJECTIVE

To review causal mutations and genotype-phenotype correlation in 480 Brazilian patients.

METHODS

DNA was extracted from 158 salt-wasters (SWs), 116 simple virilizing (SV), and 206 nonclassical (NC) patients. Fourteen point mutations were screened by allele-specific PCR, large rearrangements by Southern blotting/MLPA, and sequencing was performed in those with incomplete genotype. The gene founder effect was analyzed by microsatellite studies. Patients were divided into six genotypes (Null; A: <2%; B: 3-7%; C: >20% of residual enzymatic activity (EA); D: unknown EA; E: incomplete genotype).

RESULTS

Targeted methodologies defined genotype in 87.6% of classical and in 80% of NC patients and the addition of sequencing in 100 and 83.5%, respectively. The most frequent mutations were p.V281L (26.6% of alleles), IVS2-13A/C>G (21.1%), and p.I172N (7.5%); seven rare mutations and one novel mutation (p.E351V) were identified. Gene founder effect was observed in all but one (p.W19X) mutation. Null, A, B, and C genotypes correlated with SW (88%), SW (70%), SV (98%), and NC forms (100%), respectively. In group D, the p.E351V mutation correlated with classical form and group E comprised exclusively NC-patients. ACTH-stimulated 17OHP level of 44.3ng/mL was the best cutoff to identify NC-patients carrying severe mutations.

CONCLUSIONS

We identified a good genotype-phenotype correlation in CAH, providing useful data regarding prediction of disease's severity; moreover, we suggest that ACTH-stimulated 17OHP levels could predict carrier status for severe mutations. Sequencing is essential to optimize molecular diagnosis in Brazilian CAH patients.

A novel androgen receptor gene mutation in a patient with congenital adrenal hyperplasia associated with penoscrotal hypospadias

Congenital adrenal hyperplasia (CAH) associated with penoscrotal hypospadias is a rare case of disorders of sex development. Here, we report clinical, genetic, biochemical, and molecular findings in a 2-year-old infant with CAH and penoscrotal hypospadias. Chromosomal analysis revealed 46,XX karyotype. Hormonal investigations indicated low levels of cortisol and elevated levels of testosterone, 17-hydroxyprogesterone, and androstenedione hormone. Molecular genetic testing of androgen receptor (AR) gene identified a novel homozygous missense mutation of single nucleotide transition G to A at position 2058 (GenBank accession number GU784855), resulting in amino acid interchange alanine to threonine at codon 566 in exon 2 (Ala566Thr) (GenBank Protein_id ADD26777.1). The nature of the mutation presented is in the highly conserved DNA-binding domain of the AR gene. The novel mutation identified in the rare genetic disorder provides additional support to the previously reported genotype-phenotype correlations, and our finding has expanded the spectrum of known mutations of the AR gene.

Relationship of 2D:4D finger ratio with androgen receptor CAG and GGN repeat polymorphism

OBJECTIVES

The relative length of the second-to-fourth digits (2D:4D) has been linked with prenatal androgen in humans. A recent study shows that the 2D:4D ratio in mice is controlled by the balance of androgen to estrogen signaling during a narrow window of digit development. Androgen receptor (AR) activity is higher in digit 4 than in digit 2, and inactivation of AR decreases growth of digit 4, which causes a higher 2D:4D ratio. At the molecular level, the effect of androgens is mediated through the activation of AR. The CAG/GGN repeat polymorphisms of the AR gene are associated with AR activity. Here, we investigate the effect of CAG/GGN repeat polymorphisms in AR on 2D:4D in Chinese.

METHODS

Digit lengths of the second and fourth fingers were measured from photocopies of the ventral surface of the hand and by actual finger measurements. We genotyped AR polymorphisms by ABI 3730 DNA analyzer.

RESULTS

We found that left hand 2D:4D ratio was longer than that of the right hand both in males and in females. We failed to find any relationship between CAG / GGN alleles and the left hand, right hand, right minus left-hand or mean hand 2D:4D ratios (all, r < 0.20, P > 0.05).

CONCLUSIONS

In this study, we first found that the left hand 2D:4D ratio was longer than that of the right hand in both males and females. However, we found that both CAG and GGN alleles were not associated with the left hand, right hand, right minus left-hand or mean hand 2D:4D ratios.

Adult women with 21-hydroxylase deficient congenital adrenal hyperplasia, surgical and psychological aspects

PURPOSE OF REVIEW

Congenital adrenal hyperplasia (CAH) due to a CYP21A2 deficiency results in prenatal androgen exposure and virilization of the external genitalia. The surgical procedures, indications, timing, and methods used have come under debate during the past decade. The androgen effect on later behaviors adds to the complexity of the situation for these women. The purpose of this review is to update physicians on recent findings regarding the outcome of feminizing surgery, infertility, quality of life (QoL), and psychosexual aspects in women with CAH.

RECENT FINDINGS

Surgical outcome, also for the more modern techniques used today, has not been entirely satisfactory and QoL assessments paint a dark picture. All psychological effects assessed show a spectrum of severity correlating with the CYP21A2 genotype or disease severity. The prevailing recommendation for sex of rearing is to let all patients with the 46,XX karyotype grow up as girls. This notion has now been challenged regarding patients with the most extreme virilization of genitalia.

SUMMARY

There are large differences in outcome depending on the severity of the disease or CYP21A2 mutation. Care needs to be individualized and centralized to specialized multidisciplinary teams. Feminizing surgery is still not satisfactory for all patients. More studies regarding sex identity are needed.