Our results indicate that isolated 46,XY and 46,XX DSD can be assigned to two separate regulatory regions, XYSR and XXSR, far upstream of SOX9. The 1.9 kb SRY-responsive subfragment from the XYSR might constitute the core of the Sertoli-cell enhancer of human SOX9, representing the so far missing link in the genetic cascade of male sex determination.

Conversion of testosterone (T) to dihydrotestosterone (DHT) in genital tissue is catalysed by the enzyme 5 alpha-reductase 2, which is encoded by the SRD5A2 gene. The potent androgen DHT is required for full masculinization of the external genitalia. Mutations of the SRD5A2 gene inhibit enzyme activity, diminish DHT formation, and hence cause masculinization defects of varying degree. The classical syndrome, formerly described as pseudovaginal perineoscrotal hypospadias, is characterized by a predominantly female phenotype at birth and significant virilization without gynecomastia at puberty. We investigated nine patients with steroid 5 alpha-reductase 2 deficiency (SRD). Phenotypes, which were classified according to the severity of the masculinization defect, varied between completely female (SRD type 5), predominantly female (SRD type 4), ambiguous (SRD type 3), predominantly male with micropenis and hypospadias (SRD type 2), and completely male without overt signs of undermasculinization (SRD type 1). T/DHT-ratios were highly increased ( > 50) in the classical syndrome (SRD type 5), but variable in the less severe affected patients (SRD types 1-4) (14-35). Mutations in the SRD5A2 gene had been characterized using PCR-SSCP analysis and direct DNA sequencing. A small deletion was encountered in two patients, while all other patients had single base mutations which result in amino acid substitutions. We conclude that phenotypes may vary widely in patients with SRD5A2 gene mutations spanning the whole range from completely female to normal male without distinctive clinical signs of the disease. Hence, steroid 5 alpha-reductase deficiency should be considered not only in sex reversed patients with female or ambiguous phenotypes, but also in those with mild symptoms of undermasculinization as encountered in patients with hypospadias and/or micropenis. A classification based on the severity of the masculinization defect may be used for correlation of phenotypes with enzyme activities and genotypes, and for comparisons of phenotypes between different patients as the basis for clinical decisions to be made in patients with pseudohermaphroditism due to steroid 5 alpha-reductase 2 deficiency.

To study the relationship between abnormal Sertoli cell differentiation and spermatogenic impairment, we examined the expression of Sertoli cell markers normally lost at puberty, cytokeratin 18 (CK18), anti-Müllerian hormone (AMH) and M2A antigen, in three children (aged 1-2 years), 50 adults (aged 19-45 years) with obstructive or non-obstructive azoospermia or oligozoospermia, and six patients (aged 1-18 years) with 5 alpha-reductase deficiency. There was CK18 and/or AMH expression, but never M2A antigen expression, associated with spermatogonial arrest or Sertoli cell-only (SCO) syndrome in infertile men. Loss of M2A antigen suggests the transition of Sertoli cells to an adult phenotype, while CK18 and/or AMH expression may be a manifestation of de-differentiation of Sertoli cells. In 5 alpha-reductase deficiency, there was a sequential loss of CK18, M2A antigen and AMH around puberty, associated with partial spermatogenesis. The persistence of immature Sertoli cells expressing M2A antigen was associated with prepubertal seminiferous cords and SCO syndrome. Therefore, 5 alpha-reductase deficiency may prevent the maturation of Sertoli cells, resulting in impairment of spermatogenesis, and loss of M2A antigen expression coincides with a critical step in the Sertoli cell maturation. High follicle stimulating hormone concentrations due to failure of normal Sertoli cell differentiation indicate a normal development pattern of the hypothalamic-pituitary-gonadal axis.

No abstract

Conversion of testosterone (T) to dihydrotestosterone (DHT) in genital tissue is catalysed by the enzyme 5α‐reductase 2, which is encoded by the SRD5A2 gene. The potent androgen DHT is required for full masculinization of the external genitalia. Mutations of the SRD5A2 gene inhibit enzyme activity, diminish DHT formation, and hence cause masculinization defects of varying degree. The classical syndrome, formerly described as pseudovaginal perineoscrotal hypospadias, is characterized by a predominantly female phenotype at birth and significant virtilization without gynecomastia at puberty. We investigated nine patients with steroid 5α‐reductase 2 deficiency (SRD). Phenotypes, which were classified according to the severity of the masculinization defect, varied between completely female (SRD type 5), predominantly female (SRD type 4), ambiguous (SRD type 3), predominantly male with micropenis and hypospadias (SRD type 2), and completely male without overt signs of undermasculinization (SRD type 1). T/DHT‐ratios were highly increased (>50) in the classical syndrome (SRD type 5), but variable in the less severe affected patients (SRD types 1–4) (14–35). Mutations in the SRD5A2 gene had been characterized using PCR‐SSCP analysis and direct DNA sequencing. A small deletion was encountered in two patients, while all other patients had single base mutations which result in amino acid substitutions. We conclude that phenotypes may vary widely in patients with SRD5A2 gene mutations spanning the whole range from completely female to normal male without distinctive clinical signs of the disease. Hence, steroid 5α‐reductase deficiency should be considered not only in sex reversed patients with female or ambiguous phenotypes, but also in those with mild symptoms of undermasculinization as encountered in patients with hypospadias and/or micropenis. A classification based on the severity of the masculinization defect may be used for correlation of phenotypes with enzyme activities and genotypes, and for comparisons of phenotypes between different patients as the basis for clinical decisions to be made in patients with pseudohermaphroditism due to steroid 5α‐reductase 2 deficiency. © 1996 Wiley‐Liss, Inc.

Patients with CAH and complete virilization have a high risk of being diagnosed late. There are major problems and uncertainties of the patients' families and the treating physicians concerning gender assignment. Gender identity is disturbed in some patients. In addition, multiple surgical procedures are necessary and short stature as well as central precocious puberty might be important to avoid late sequelae. While some surgical interventions are probably unavoidable, most of these issues could be resolved with an early diagnosis. Thus, especially for these patients, a neonatal screening programme for CAH would be of paramount importance.

Background: Despite treatment, the mean final height (FH) of patients with classic congenital adrenal hyperplasia (CAH) is below the mean height of a normal population. Aims:To show that CAH patients can achieve their target height (TH), 39 adult subjects, whose therapy had started in infancy, were studied in a retrospective analysis. All height SDS were corrected so that they related to TH SDS. Patients: Group 1: patients born before 1975 (n = 13) had received prednisolone, at doses equivalent to hydrocortisone 39.4 ± 15.6 mg/m² BSA daily, together with DOCA in the first 2 years of life. Group 2: patients born from 1975 to 1986 (n = 26) received at this age lower hydrocortisone doses (16.4 ± 6.9 mg/m² BSA daily, divided 8 hourly; p < 0.001) combined with fludrocortisone, had outpatient visits every 3 months and bone age (BA) estimation every 6 months. Results: Patients of group 1 (FH SDS –1.2 ± 1.0) had a poor outcome, whereas patients of group 2 (FH SDS 0.1 ± 0.9; p = 0.01) achieved their TH. Conclusion: Combined corticoid administration adjusted quarterly to keep height, BMI, blood pressure and BA within normal limits resulted in FH close to TH in patients with classic CAH.

We studied 95 patients and their relatives with the classical salt wasting (SW) and simple virilizing (SV) form of CAH. SSCP/heteroduplex analysis allowed fast and efficient screening for the most common 21-hydroxylase mutations (e.g. deletions, splice site mutation in intron 2 (bp 656), Ile172Asn mutation in exon 4) and determination of the relative intensities of CYP21A and CYP21B genes. The splice site mutation in intron 2 was found as the most frequent cause of 21-hydroxylase deficiency (35% of our patients). There is a strong genetic association between the mutation in intron 2 and the SW form of CAH. On the other hand, about 20% of our patients with the intron 2 mutation have the SV phenotype. Interestingly, homozygous splice site mutations in intron 2 were also detected in some parents or other relatives with no phenotypic changes typical for CAH (clinical evaluation, steroid hormone levels). In those patients with SV-CAH and especially in the relatives with the homozygous intron 2 mutation and an unaffected phenotype, the splice site mutation could be "leaky". mRNA-splicing in the adrenal cortex should result in a high degree of normal mRNA species. This is in contrast to in vitro expression studies of CYP21B genes containing the intron 2 mutation, performed by other groups. However, the results of in vitro expression studies are not always reflecting the in vivo conditions in the adrenal cortex. This situation is in good agreement with the variable degree of normal spliced mRNA and different phenotypic severity in intron mutations found in thalassemia.