Identification of a common molecular basis for combined 17 alpha-hydroxylase/17,20-lyase deficiency in two Mennonite families

Classic genetic and hormonal switches during fetal sex development and beyond

Critical genetic and hormonal switches characterize fetal sex development in humans. They are decisive for gonadal sex determination and subsequent differentiation of the genital and somatic sex phenotype. Only at the first glace these switches seem to behave like the dual 0 and 1 system in computer sciences and lead invariably to either typically male or female phenotypes. More recent data indicate that this model is insufficient. In addition, in case of distinct mutations, many of these switches may act variably, causing a functional continuum of alterations of gene functions and -dosages, enzymatic activities, sex hormone levels, and sex hormone sensitivity, giving rise to a broad clinical spectrum of biological differences of sex development (DSD) and potentially diversity of genital and somatic sex phenotypes. The gonadal anlage is initially a bipotential organ that can develop either into a testis or an ovary. Sex-determining region Y (SRY) is the most important upstream switch of gonadal sex determination inducing SOX9 further downstream, leading to testicular Sertoli cell differentiation and the repression of ovarian pathways. If SRY is absent (virtually "switched off"), e. g., in 46,XX females, RSPO1, WNT4, FOXL2, and other factors repress the male pathway and promote ovarian development. Testosterone and its more potent derivative, dihydrotestosterone (DHT) as well as AMH, are the most important upstream hormonal switches in phenotypic sex differentiation. Masculinization of the genitalia, i. e., external genital midline fusion forming the scrotum, growth of the genital tubercle, and Wolffian duct development, occurs in response to testosterone synthesized by steroidogenic cells in the testis. Müllerian ducts will not develop into a uterus and fallopian tubes in males due to Anti-Müllerian-Hormone (AMH) produced by the Sertoli cells. The functionality of these two hormone-dependent switches is ensured by their corresponding receptors, the intracellular androgen receptor (AR) and the transmembrane AMH type II receptor. The absence of high testosterone and high AMH is crucial for anatomically female genital development during fetal life. Recent technological advances, including single-cell and spatial transcriptomics, will likely shed more light on the nature of these molecular switches.

CYP17A1 mutations identified in 17 Chinese patients with 17α-hydroxylase/17,20-lyase deficiency

CONTEXT

17α-hydroxylase deficiency (17OHD) is a relatively rare disease, accounting for about 1% of congenital adrenal hyperplasia cases. The CYP17A1 gene mutation can lead to this disease. Human CYP17A1 gene is located on chromosome 10q24.3. It consists of eight exons encoding 508 amino acids. To date, more than 50 mutations in exons and introns of the CYP17A1 gene have been reported to cause complete or partial 17OHD.

OBJECTIVE

The aim of this study was to investigate the CYP17A1 gene mutation types in 17 Chinese patients, containing 11 complete and six partial 17OHD patients.

SETTING

We conducted the study in the Department of Obstetrics and Gynecology of Peking Union Medical College Hospital.

PATIENTS

Seventeen patients were studied with complete or partial 17OHD.

MAIN OUTCOME MEASURES

The CYP17A1 gene was sequenced and we measured steroid and sex hormone levels.

RESULTS

Analysis of the CYP17A1 gene in our patients revealed 12 different kinds of mutation. Two mutations (IVS1-1G>A and L209P) were novel mutations. Mutation c.985_987delTACinsAA (Y329KfsX418) in Exon 6 was the most common mutation in Chinese patients, accounting for 50 percents of the mutant alleles (17/34). Exon 6 was the hot spot since most mutations were detected in this exon (59%, 20/34 alleles). There was no mutation detected in the Exons 4 and 5.

Partial 17alpha-hydroxylase/17,20-lyase deficiency-clinical report of five Chinese 46,XX cases

OBJECTIVES

To summarize the clinical characteristics of partial 17alpha-hydroxylase/17,20-lyase deficiency (17OHD) in 46,XX Chinese patients.

METHODS

Five cases of 46,XX partial 17OHD from Peking Union Medical College Hospital were studied retrospectively by summarizing and analyzing their clinical data. The molecular pathogenic mechanisms involved are discussed after reviewing the literature.

RESULTS

Both complete and partial 17OHD patients have hypergonadotropic hypogonadism and elevated serum levels of adrenocorticotropic hormone and mineralocorticoids. The clinical characteristics of partial 17OHD are different from those of complete 17OHD; patients with the former having various degrees of estrogenic and androgenic impacts such as the development of breasts and pubic hair, and oligomenorrhea or secondary amenorrhea. Elevated serum progesterone with or without elevated serum 17alpha-hydroxyprogesterone and recurrent ovarian cysts are typical manifestations of partial 17OHD. Furthermore, hypokalemic hypertension may be absent in partial 17OHD. The 46,XX partial 17OHD should be differentiated from pure gonadal dysgenesis, premature ovarian failure and polycystic ovarian syndrome. It has been reported that specific mutations of the CYP17 gene can cause partial loss of 17alpha-hydroxylase/17,20-lyase activities or dissociation between the 17alpha-hydroxylase and the 17,20-lyase functions. Oral contraceptive pills are effective for artificial menstruation, but not for the correction of hormone deficiency. A low dose of cortisol should be prescribed in the presence of hypokalemic hypertension.

CONCLUSION

The congenital partial 17OHD should be included in the differential diagnosis of menstrual disorders. In these cases, elevated progesterone offers a valuable clue for further investigation.

Unique disease heritage of the Dutch-German Mennonite population

The Dutch-German Mennonites are a religious isolate with foundational roots in the 16th century. A tradition of endogamy, large families, detailed genealogical records, and a unique disease history all contribute to making this a valuable population for genetic studies. Such studies in the Dutch-German Mennonite population have already contributed to the identification of the causative genes in several conditions such as the incomplete form of X-linked congenital stationary night blindness (CSNB2; previously iCSNB) and hypophosphatasia (HOPS), as well as the discovery of founder mutations within established disease genes (MYBPC1, CYP17alpha). The Dutch-German Mennonite population provides a strong resource for gene discovery and could lead to the identification of additional disease genes with relevance to the general population. In addition, further research developments should enhance delivery of clinical genetic services to this unique community. In the current review we discuss 31 genetic conditions, including 17 with identified gene mutations, within the Dutch-German Mennonite population.

17alpha-hydroxylase deficiency : biochemical and molecular findings in two sisters and their family

OBJECTIVE

To search for molecular changes in two Argentinian sisters with a clinical and biochemical diagnosis of 17alpha-hydroxylase deficiency.

SUBJECTS

Both patients had 46 XX karyotype, with sexual infantilism, primary amenorrhea, and hypertension. Other member of the first degree family did not have this deficiency. HORMONAL RESULTS: The patients showed high levels of gonadotrophins and progesterone along with very low cortisol and androgen levels. Basal levels of corticosterone were very high, but aldosterone was normal. Both steroids had a high response after adrenocorticotropic hormone (ACTH) stimulation, with no changes in 17-hydroxyl progesterone and cortisol levels. Progesterone, corticosterone, and aldosterone decreased with the dexamethasone test, without modifications in 17-hydroxyl progesterone and cortisol levels. A corticosterone/aldosterone ratio was calculated from the results of the stimulation test; the ratios were similar in both patients. On administration of the ACTH test, both parents and one sister (S2) showed a marked response in corticosterone levels, their corticosterone/aldosterone ratios were also similar to each other and similar to the patients. MOLECULAR RESULTS: Molecular studies in the cytochrome P450 17 (CYP17) gene showed that exon 8 had a 4 bp duplication at codon 480 (CATC) in the two patients and their mother and in exon 1, a C to T transition at codon 96 was identified, changing CGG into TGG in the two patients, S2, and their father.

CONCLUSIONS

Both patients were shown to be compound heterozygous, carrying different alleles in exon 1 and exon 8, inherited from their father and mother, respectively. The molecular results obtained on S2 confirmed the heterozygosity suggested by the stimulated hormonal test and corticosterone/aldosterone ratio.

Overview of steroidogenic enzymes in the pathway from cholesterol to active steroid hormones

Significant advances have taken place in our knowledge of the enzymes involved in steroid hormone biosynthesis since the last comprehensive review in 1988. Major developments include the cloning, identification, and characterization of multiple isoforms of 3beta-hydroxysteroid dehydrogenase, which play a critical role in the biosynthesis of all steroid hormones and 17beta-hydroxysteroid dehydrogenase where specific isoforms are essential for the final step in active steroid hormone biosynthesis. Advances have taken place in our understanding of the unique manner that determines tissue-specific expression of P450aromatase through the utilization of alternative promoters. In recent years, evidence has been obtained for the expression of steroidogenic enzymes in the nervous system and in cardiac tissue, indicating that these tissues may be involved in the biosynthesis of steroid hormones acting in an autocrine or paracrine manner. This review presents a detailed description of the enzymes involved in the biosynthesis of active steroid hormones, with emphasis on the human and mouse enzymes and their expression in gonads, adrenal glands, and placenta.

P450c17 deficiency in Brazilian patients: biochemical diagnosis through progesterone levels confirmed by CYP17 genotyping

P450c17 deficiency is an autosomal recessive disorder and a rare cause of congenital adrenal hyperplasia characterized by hypertension, hypokalemia, and impaired production of sex hormones. We performed a clinical, hormonal, and molecular study of 11 patients from 6 Brazilian families with the combined 17alpha-hydroxylase/17,20-lyase deficiency phenotype. All patients had elevated basal serum levels of progesterone (1.8-38 ng/ml; 0.57-12 pmol/liter) and suppressed plasma renin activity. CYP17 genotyping identified 5 missense mutations. The compound heterozygous mutation R362C/W406R was found in 1 family, whereas the homozygous mutations R96W, Y329D, and P428L were seen in the other 5 families. The R96W mutation has been described as the cause of p450c17 deficiency in Caucasian patients. The other mutations were not found in 50 normal subjects screened by allele-specific oligonucleotide hybridization (Y329D, R362C, and W406R) or digestion with HphI (P428L) and were recently found in other Brazilian patients. Therefore, we elucidated the genotype of 11 individuals with p450c17 deficiency and concluded that basal progesterone measurement is a useful marker of p450c17 deficiency and that its use should reduce the misdiagnosis of this deficiency in patients presenting with male pseudohermaphroditism, primary or secondary amenorrhea, and mineralocorticoid excess syndrome.

Looking for selectivity among cytochrome P450s inhibitors

Cytochrome P450s 19 and 17 are very important pharmacological targets in two different fields of cancer chemotherapy. We present here a theoretical study aimed at explaining the molecular basis of inhibitor affinity and selectivity for either P450 19 or P450 17. Docking simulations of two compounds pointed out the major physicochemical features associated with inhibitory activity. Our results, in agreement with site-directed mutagenesis experiments, could be of relevant utility when designing new P450 19 and P450 17 inhibitors.

The genetics, pathophysiology, and management of human deficiencies of P450c17

P450c17 commands a central role in human steroidogenesis as the qualitative regulator of steroid hormone flux. Consequently, the study of P450c17 deficiencies in human beings serves to illustrate many aspects of the physiology of steroid biosynthesis and to demonstrate salient features of the genetics and biochemistry of P450c17 itself. Furthermore, classic 17-hydroxylase deficiency was first described in patients with sexual infantilism and hypertension, but it is now recognized that partial and selective forms of P450c17 deficiencies also exist. These patients demonstrate a range of phenotypes, illustrating the multiple roles of P450c17 in human biology. This article reviews the genetics and biochemistry of P450c17 as a prelude for understanding the pathophysiology of these diseases and approaches to their diagnosis and management.

Compound heterozygous mutations (PHE53/54DEL and HIS373LEU) of the P450c17 gene result in a 17alpha-hydroxylase/17,20-lyase deficient male pseudohermaphrodite with unambiguous external genitalia

The autosomal recessive disease 17alpha-hydroxylase/17,20-lyase deficiency is characterized by mutation of the P450c17 enzyme, which catalyzes 17alpha-hydroxylation and 17,20-lysis in the steroidogenic pathways. Although 17 mutations of this enzyme have been reported, only a few of them resulted in a completely unambiguous phenotype of female external genitalia in 46, XY individuals. We report here a Japanese patient with a 46,XY karyotype, who showed such a unambiguous female external genitalia. Nucleotide sequencing of the P450c17 gene revealed the patient to be a compound heterozygote carrying two different mutations (PHE53/54DEL in exon 1 and HIS373LEU in exon 6). As these mutations have been previously detected in unrelated Japanese patients, it is confirmed that these mutations accumulate regionally. Since these mutations could be screened by a multiple genotyping method, the method is applicable when 17alpha-hydroxylase/17, 20-lyase deficiency is suspected in Japanese patients.

17alpha-hydroxylase/17,20-lyase deficiency as a model to study enzymatic activity regulation: role of phosphorylation

Cytochrome P450 17alpha-hydroxylase (CYP17) is a single gene-encoded protein with two activities: 17alpha-hydroxylase and 17,20-lyase. The two catalytic activities are differentially regulated in health and disease. We took advantage of naturally occurring human mutations to understand the molecular bases of this differential regulation. We identified eight novel mutations in the CYP17 gene, different in nature and spread throughout the gene. As posttranslational modifications appear to be important for activity control, we investigated the phosphorylation state of wild-type and mutant CYP17 proteins. Although phospholabeled protein was seen when the wild-type and most mutant proteins were expressed, no phosphorylation was detected for the F417C mutant. F417C is the only 17,20-lyase deficiency case confirmed at the molecular level and represents the first phosphorylation CYP17-deficient mutant. In search of the physiological agents involved in this process, the effect of cAMP was tested on activity and phosphorylation state of our mutant CYP17 proteins. cAMP stimulates activity and phosphorylation in all cases, except in the F417C and R35L mutants. The lack of response to the physiological second messenger might explain the different phenotypes. The F417C mutant protein, which is already shown to be associated with the lack of electron transfer, provides for the first time a link between the electron transfer system and the phosphorylation state of the CYP17 enzyme in the control of 17,20-lyase activity.

The homeodomain protein Pbx1 is involved in cAMP-dependent transcription of human CYP17

Pbx1 is a homeodomain transcription factor involved in cAMP-dependent transcriptional regulation of the bovine CYP17 gene. In this study, we have investigated the involvement of Pbx1 in the transcriptional regulation of the human CYP17 gene. Although a sequence identical to previously determined Pbx-binding sites is not present in the promoter region of the human CYP17 gene, three putative Pbx-binding sites are identified by sequence similarity analysis. Coexpression of Pbx1 and a catalytic subunit of protein kinase A (PKA) greatly enhances reporter gene transcription via the 5'-flanking region of the human CYP17 gene. Upon gel shift analysis utilizing nuclear extracts from human adrenal H295R cells, one of the three putative Pbx1-binding sites, -250/-241 bp, shows the typical intense doublet observed with other Pbx-binding sites. 5'-Deletion analyses of the reporter construct containing this Pbx-binding site showed approximately sixfold induction by coexpression of Pbx1 and PKA compared to the basal transcription, suggesting that Pbx1 binds the -250/-241 bp sequence and participates in cAMP-dependent regulation of the human CYP17 gene.

17 alpha-Hydroxylase/17,20-lyase defects

Congenital adrenal hyperplasia due to 17 alpha-hydroxylase/17/20-lyase deficiency is caused by genetic defects in the gene encoding P450c17 (CYP17). To date, 18 different mutations in 27 individuals have been identified and all of them are located in the coding region of CYP17. Several mutations have been reconstructed in human P450c17 cDNA and expressed in COS cells to characterize the kinetic properties of 17 alpha-hydroxylase and 17,20-lyase activities. The molecular bases of cases clinically reported as 17 alpha-hydroxylase deficiency have turned out to result from complete or partial combined deficiencies of 17 alpha-hydroxylase/17,20-lyase. The elucidation of the molecular bases generally explains the patient's clinical profiles including the sexual phenotype of the external genitalia. In one case initially reported as isolated 17,20-lyase deficiency, the molecular basis was found to be partial combined deficiency of both activities, somewhat discordant with the patient's clinical profile. However, the patient was subsequently found to have 17 alpha-hydroxylase deficiency, suggesting involvements of age-dependent unknown factors affecting P450c17 activity.

Genetic diseases of steroid metabolism

All major classes of biologically active steroid hormones (progestins, mineralocorticoids, glucocorticoids, and sex steroids) are synthesized from cholesterol through 11 different bioconversions. With the exception of 5 alpha-reductase, all the enzymes mediating these reactions fall into two classes, cytochromes P450 and short-chain dehydrogenases. Cytochromes P450 are heme-containing membrane-bound proteins with molecular weights of approximately 50,000 that utilize molecular oxygen and electrons from NADPH-dependent accessory proteins to hydroxylate substrates. Short-chain dehydrogenases have molecular weights of 30,000-40,000, have tyrosine and lysine residues at the active site, and remove a hydride from the substrate, transferring the electrons of the hydride to NAD+ or NADP+. In most cases, this reaction is reversible so that the dehydrogenase can also function as a reductase under appropriate conditions. Inherited disorders in enzymes required for steroid biosynthesis have varying effects. Defects that prevent cortisol from being synthesized are referred to collectively as congenital adrenal hyperplasia. Because the enzymes required for cortisol biosynthesis in the adrenal cortex are in many cases required for the synthesis of mineralocorticoids and/or sex steroids, these classes of steroids may also not be synthesized normally. Thus, cholesterol desmolase and 3 beta-hydroxysteroid dehydrogenase deficiencies affect synthesis of all classes of steroids in both the adrenals and gonads. Steroid 21-hydroxylase deficiency, the most common cause (> 90% of cases) of congenital adrenal hyperplasia, can affect both mineralocorticoid and glucocorticoid synthesis, but androgen secretion is usually abnormally high due to shunting of accumulated precursors into this pathway. Excessive secretion of androgens and mineralocorticoids occurs in 11 beta-hydroxylase deficiency (the second most frequent form of congenital adrenal hyperplasia). Mineralocorticoid excess is also seen in 17 alpha-hydroxylase deficiency, but in this disorder sex steroid synthesis is defective. All defects that affect estrogen synthesis (deficiencies of cholesterol desmolase, 3 beta-hydroxysteroid dehydrogenase, 17 alpha-hydroxylase, aromatase, and 17 beta-hydroxysteroid dehydrogenase) are very rare, suggesting that the inability to synthesize placental estrogens may adversely affect fetal survival. A number of enzymes are expressed at sites of steroid action and regulate the amount of active steroid available to steroid receptors. Steroid 5 alpha-reductase converts testosterone to the more active dihydrotestosterone. Deficiency of this activity leads to incomplete development of male genitalia; 17 beta-hydroxysteroid dehydrogenase deficiency has similar phenotypic effects.(ABSTRACT TRUNCATED AT 400 WORDS)

Diagnosis and treatment of 17-hydroxylase deficiency

Leading symptoms of 17-hydroxylase/17,20-lyase deficiency in childhood are hypertension and hypokalemia. We found this enzyme defect in 3 phenotypically female siblings aged 12, 15 and 16 years. Two of the sibs have a 46,XY chromosome pattern, the third is genetically female. Pubertal development did not occur. Both of the 46,XY sibs have male internal and female external genitalia. The 46,XX sister has normal female internal genitalia. At the time of diagnosis, two of the three siblings had hypertension (RR between 190/135 and 160/110 mmHg). Two of the three siblings had low serum potassium and metabolic alkalosis. All three patients had excessively high plasma levels of 11-deoxycorticosterone (DOC) and corticosterone. Aldosterone was also elevated whereas plasma renin activity was suppressed. Plasma cortisol and its 17-hydroxylated precursors were low, as were plasma testosterone, dihydroepiandrosterone sulphate and estradiol, while the gonadotropins LH and FSH were elevated in all three patients. We studied the steroid profiles of these three patients during long term glucocorticoid treatment with dexamethasone, which is now followed for 13 years. Blood pressure and serum potassium became normal. Plasma aldosterone, corticosterone and DOC were clearly lower but not fully normalized. The two genetically male sisters obtained estrogens for induction of female secondary sex characteristics. The third 46,XX sister has normal menstruations during substitution with cyclic estrogen/gestagen therapy. All three patients lack pubic and axillary hair, and reached normal adult heights both for phenotypic sex and for target height. The psychosocial orientation is female in all of them. Apart from rare reports of development of malignant hypertension, prognosis is better than in other enzyme deficiencies causing congenital adrenal hyperplasia since no Addisonian crises occur due to DOC and corticosterone overproduction resulting in apparently normal endogenous glucocorticoid activity.

Molecular basis of 17α-hydroxylase/17,20-lyase deficiency

17α-Hydroxylase deficiency is characterized by a defect in either or both of 17α-hydroxylase and 17,20-lyase activities, based on the fact that a single polypeptide P450c17 can catalyze both reactions. The clinical manifestations of 17α-hydroxylase/17,20-lyase deficiency seem to be more heterogeneous than expected, varying from the classical type to less symptomatic forms as also observed in 21-hydroxylase deficiency. We have sequenced all eight exons of the CYP17 (P450c17) gene in DNA from several patients, reconstructed the mutations in a human P450c17 cDNA and expressed the mutant P450c17 in COS 1 cells to characterize the kinetic properties of 17α-hydroxylase and 17,20-lyase activities. The molecular bases of cases clinically reported as 17α-hydroxylase deficiency have turned out to be complete or partial combined deficiencies of 17α-hydroxylase/17,20-lyase. The elucidation of the molecular basis generally explains the patient's clinical profiles including the sexual phenotype of the external genitalia. In one case clinically reported as isolated 17,20-lyase deficiency, the molecular basis was found to be partial combined deficiency of both activities, somewhat discordant with the patient's clinical profile. Based on the results obtained so far we can predict that those 17α-hydroxylase deficient individuals having a homozygous stop codon in the CYP17 gene positioned at the amino terminal side of the P450c17 heme-binding cysteine (442) will all have the same phenotype. However those individuals having homozygous missense mutations or those who are compound heterozygotes having a missense mutation in at least one CYP17 allele will display their own unique phenotype which clinically will be subtly different from all others.

Molecular basis of apparent isolated 17,20-lyase deficiency: compound heterozygous mutations in the C-terminal region (Arg(496)----Cys, Gln(461)----Stop) actually cause combined 17 alpha-hydroxylase/17,20-lyase deficiency

The molecular defect in a reported case of isolated 17,20-lyase deficiency in a 46XY individual has been elucidated. The patient was found to be a compound heterozygote, carrying two different mutant alleles in the CYP17 gene. One allele contains a point mutation of arginine (CGC) to cysteine (TGC) at amino acid 496 in exon 8. The second allele contains a stop codon (TAG) in place of glutamine (CAG) at position 461 in exon 8 which is located 19 amino acids to the carboxy-terminal side of the P-450(17) alpha heme binding cysteine. COS-1 cells transfected with cDNAs containing one or the other of these mutations showed dramatically reduced 17 alpha-hydroxylase and 17,20-lyase activities relative to cells transfected with the wild type P-450(17) alpha cDNA. While the in vitro data in COS 1 cells can explain the patient's physical phenotype, with female external genitalia, it was somewhat discordant with the clinical expression of isolated 17,20-lyase deficiency with relative preservation of 17 alpha-hydroxylase activity in vivo. In addition to the expression studies of these two examples of mutants in the C-terminal region of cytochrome P-450(17) alpha, a third mutant cDNA construct containing a 4-base duplication at codon 480 previously found in patients with combined 17 alpha-hydroxylase/17,20-lyase deficiency was also expressed in COS-1 cells. This expressed protein was completely inactive with respect to both activities, supporting the biochemical findings in serum and in vitro biochemical data obtained using a testis from the patient. The results from these patients clearly indicate the importance of the C-terminal region of human P-450(17) alpha in its enzymatic activities.

Canadian Mennonites and individuals residing in the Friesland region of The Netherlands share the same molecular basis of 17 alpha-hydroxylase deficiency

A common mutation within the CYP17 gene that causes 17 alpha-hydroxylase deficiency, a form of congenital adrenal hyperplasia, has been found by direct sequencing of polymerase chain reaction (PCR) fragments of genomic DNA from six families residing in the Friesland region of the Netherlands. The mutation is a 4-base duplication within exon 8 of the CYP17 gene, which alters the reading frame encoding the C-terminal 26 amino acids of cytochrome P45017 alpha. This mutation has previously been found in two Canadian patients who are members of ostensibly unrelated Mennonite families. The Mennonite Churches derive their name from Menno Simons, an early leader of the sect in Friesland. Presumably this 4-base duplication appeared within the Friesian population prior to emigration of the Mennonites from the Netherlands.

Deficiency of 17 alpha-hydroxylase associated with absent gonads

A phenotypic female presented initially at the age of 17 years with amenorrhoea and delay of sexual development. Karyotype was male, 46 XY, and as gonads were absent, a diagnosis of congenital anorchia was made. The patient was treated with oestrogen. At the age of 23 years, she re-presented with tall stature and hypertension. She then had normal female habitus but absent pubic and axillary hair. Re-investigation showed that sex steroids and cortisol were absent and established the diagnosis as 17 alpha-hydroxylase deficiency. Treatment with hydrocortisone rapidly corrected the hypertension. Ultrasound examination confirmed the absence of gonads but showed that a small uterus was present. Measurement of serum cortisol is important for recognition of such patients, but further measurements of sex steroids, particularly progesterone, are needed to prove the diagnosis. We have found no previous reports of absent gonads in 17 alpha-hydroxylase deficiency. The association remains unexplained.