17α-Hydroxylase Deficiency
(CYP17A1 deficiency: 17α-hydroxylase/17,20-lyase)

17α-hydroxylase deficiency is a rare form of congenital adrenal hyperplasia caused by reduced activity of the CYP17A1 enzyme, which catalyzes two key steps in steroidogenesis: 17α-hydroxylation and the 17,20-lyase reaction. The pathophysiological consequence is impaired synthesis of cortisol and, especially, sex steroids, with obligatory diversion of precursors toward the production of steroids with predominantly mineralocorticoid activity and toward the formation of corticosterone. Corticosterone may partially meet glucocorticoid requirements and mask classic adrenocortical insufficiency.

In clinical practice, this combination produces a highly recognizable phenotype: hypertension, often associated with hypokalemia caused by excess deoxycorticosterone, and a spectrum of hypogonadism characterized by absent pubertal development, primary amenorrhea in 46,XX individuals, and undervirilization with a female phenotype or genital ambiguity in 46,XY individuals. Diagnosis requires a rational assessment integrating clinical findings, the steroid profile and the renin-aldosterone system, followed by genetic confirmation, because accurate etiological definition guides replacement therapy, blood pressure management and long-term decisions concerning reproductive health and sex development.

17α-hydroxylase deficiency accounts for a small proportion of congenital adrenal hyperplasia cases and is considerably less common than 21-hydroxylase deficiency. Its rarity reflects the low incidence of pathogenic CYP17A1 variants in the general population, although its distribution is not uniform. Familial clusters and recurrent variants have been described in certain geographical areas and ethnic groups, with founder effects increasing the probability of disease in specific communities. Clinically, this means that family history and geographical origin may influence the pre-test probability, but they do not replace a structured diagnostic pathway.

The age at presentation tends to be later than in classic forms associated with neonatal adrenal crisis because accumulation of corticosterone and residual glucocorticoid activity may prevent overt manifestations of cortisol deficiency. Consequently, presentation often occurs during adolescence or early adulthood with delayed puberty, primary amenorrhea, absent development of secondary sexual characteristics and, concurrently, signs of mineralocorticoid excess, including hypertension, headache and hypokalemia with fatigue or muscle cramps. In 46,XY individuals, evaluation may begin earlier because of female or ambiguous external genitalia, cryptorchidism and absent virilization, whereas in 46,XX individuals the diagnosis is frequently established when puberty fails to progress or primary amenorrhea is associated with hypertension.

The main individual risk factor is carrier status within a family with known mutations, as is typical of autosomal recessive disorders. Consanguinity increases the likelihood of homozygosity for rare variants, while affected siblings or cousins should prompt early suspicion even in the absence of severe symptoms. From a clinical perspective, the absence of hyperandrogenism and the apparently normal baseline values of glucocorticoid-dependent parameters may delay recognition of the condition. Careful attention to the combined presence of hyporeninemic hypertension and hypogonadism is therefore essential.

Clinical epidemiology is also influenced by the diagnostic methods available. Access to highly specific steroid panels, including mass spectrometry, and to molecular genetic testing has increased the ability to identify partial forms and atypical phenotypes in which either the mineralocorticoid or gonadal component predominates. This variability makes it plausible that some cases remain undiagnosed or are classified as undefined secondary hypertension or functional hypogonadism, particularly when the presentation is incomplete.

Finally, vulnerability and clinical impact depend substantially on comorbidities. Patients exposed to hypertension and hypokalemia for prolonged periods have a greater cumulative cardiovascular risk, whereas prolonged hypogonadism, particularly in 46,XX individuals, may predispose to low bone mass and impaired quality of life. These factors explain why the epidemiology of 17α-hydroxylase deficiency cannot be reduced to case numbers alone but must be understood as an interaction between genetics, diagnostic access and clinical trajectories over time.

The etiology of 17α-hydroxylase deficiency is attributable to pathogenic variants of the CYP17A1 gene, which encodes cytochrome P450c17 and is expressed in the adrenal cortex and gonads. The enzyme has two functions: 17α-hydroxylase activity converts pregnenolone and progesterone into 17-hydroxylated intermediates required for cortisol synthesis, whereas 17,20-lyase activity enables the production of androgen precursors such as dehydroepiandrosterone and androstenedione. Combined or partial loss of these activities defines a phenotypic spectrum ranging from the classic form with a marked enzymatic block to partial variants in which residual enzymatic function attenuates some manifestations while preserving the characteristic clinical pattern.

From a pathogenetic perspective, the central abnormality is reduced production of cortisol, which decreases negative feedback on the pituitary gland and increases adrenocorticotropic hormone (ACTH) secretion. Chronic ACTH overstimulation causes adrenal hyperplasia and increases flux through the available steroidogenic pathways. Because the 17-hydroxylated pathway is blocked, precursors are redirected toward the synthesis of steroids with mineralocorticoid activity, particularly 11-deoxycorticosterone, and toward the production of corticosterone. Corticosterone has significant glucocorticoid activity and, although it does not fully reproduce the physiology of cortisol, it may prevent classic adrenal crisis. This explains why many patients do not develop the typical hypoglycemic instability or shock associated with glucocorticoid deficiency.

The pathophysiology of hypertension is primarily related to excess 11-deoxycorticosterone, which activates mineralocorticoid receptors in the distal nephron, increasing sodium reabsorption and potassium and hydrogen ion excretion. The result is extracellular volume expansion, suppression of renin and often functional reduction of aldosterone secretion. An important interpretative consideration is that aldosterone may be low, normal or apparently not suppressed depending on the analytical method and cross-reactivity with other steroids. The renin-aldosterone profile must therefore be interpreted together with the clinical findings and steroid profile, without drawing automatic conclusions from a single measurement.

At the gonadal level, reduced availability of androgen precursors and sex steroids causes hypergonadotropic hypogonadism or a functionally hypogonadal state, with compensatory elevation of gonadotropins and absent pubertal development. In 46,XX individuals, inadequate ovarian steroidogenesis results in poor estrogenization, absent breast development, primary amenorrhea and reduced bone mineralization. In 46,XY individuals, androgen deficiency prevents intrauterine and pubertal virilization, producing female or ambiguous external genitalia, undescended testes and absence of Müllerian structures because of anti-Müllerian hormone activity. This creates the characteristic dissociation between the external phenotype and internal anatomy.

A further pathophysiological level concerns the fine regulation of receptor signaling and enzymatic cofactors. The 17,20-lyase function may be influenced by cofactors such as cytochrome b5 and by defects in accessory proteins of the P450 electron-transfer system. Consequently, some phenotypes may be characterized predominantly by androgen deficiency with relative preservation of the glucocorticoid pathway, or by combinations that are not entirely comparable between individuals. In practice, the disease must be understood as a spectrum in which the severity of hypertension, the degree of hypokalemia and the depth of hypogonadism may not progress in parallel.

Finally, chronic exposure to mineralocorticoid excess and sex steroid deficiency produces systemic consequences, including cardiovascular remodeling, target-organ damage caused by hypertension, electrolyte abnormalities with susceptibility to arrhythmias, and reduced bone mass with a risk of osteopenia. The causal sequence nevertheless remains consistent: a genetic enzymatic defect, diversion of steroidogenic flux, elevated ACTH with adrenal hyperplasia, excess mineralocorticoid-active steroids and sex steroid deficiency, followed by clinical manifestations that emerge over time according to individual reserve and the degree of functional impairment.

The clinical manifestations of 17α-hydroxylase deficiency result from the interaction between mineralocorticoid excess and sex steroid deficiency, with a variable contribution from isolated glucocorticoid deficiency, which is often attenuated by corticosterone production. The clinical picture therefore tends to emerge progressively and may be overlooked when symptoms are considered separately. The typical natural history brings the patient to medical attention because of delayed puberty or primary amenorrhea, or because of hypertension at a young age, sometimes associated with symptomatic hypokalemia.

During the medical history, 46,XX individuals frequently report absent breast development or incomplete breast maturation, failure of menarche to occur and reduced growth of pubic and axillary hair. Fatigue, exercise intolerance and muscle cramps may be present, particularly when hypokalemia is significant. Headache, awareness of pulsations and sleep disturbances may reflect unrecognized hypertension. In 46,XY individuals, the history may include female sex assignment at birth because of female external genitalia, absent virilization during adolescence, absence of menstruation, or signs of a disorder of sex development with genital ambiguity and testes that are not palpable in the scrotum.

The physical examination should follow a sequence integrating vital signs, endocrine findings and assessment of pubertal development. Accurate measurement of blood pressure on repeated occasions is essential because hypertension may be persistent yet minimally symptomatic. The skin may not show marked hyperpigmentation despite elevated ACTH, and typical signs of classic adrenal insufficiency are often absent. In patients with hypokalemia, proximal weakness, hypotonia, reduced reflexes or tremor may occur with variable severity. Anthropometric assessment and evaluation of body composition are relevant because prolonged hypogonadism may affect fat distribution, muscle mass and bone mineral density.

Assessment of pubertal development typically shows absent or delayed secondary sexual characteristics. In 46,XX individuals, hypoestrogenism may be evident through poorly estrogenized genital mucosa and a small uterus on imaging. In phenotypically female 46,XY individuals, intra-abdominal or inguinal gonads may be suspected when the uterus and adnexa are absent. Sparse pubic and axillary hair is a useful clinical finding because it reflects adrenal androgen deficiency and distinguishes this condition from other causes of primary amenorrhea in which adrenarche is preserved.

The cardiovascular presentation may range from moderate hypertension to severe hypertension with complications, particularly when diagnosis is delayed. The combination of chronic hypertension and hypokalemia may predispose to palpitations, premature beats and reduced exercise tolerance. When hypokalemia is substantial, paresthesia, cramps and weakness may become the predominant reason for seeking medical care, while impaired pubertal development remains unrecognized until targeted endocrinological assessment is performed.

A crucial clinical consideration is that cortisol deficiency may present subtly. During physiological stress, some patients may develop marked fatigue, nausea, relative hypotension compared with their hypertensive baseline or an impaired stress response, even though classic adrenal crisis is less frequent. The medical history should therefore include recurrent infections, slow recovery from acute illness and previous hypoglycemia, without assuming that the absence of dramatic events excludes clinically relevant glucocorticoid deficiency.

17α-hydroxylase deficiency should be suspected when manifestations of mineralocorticoid excess coexist with signs of hypogonadism, particularly during adolescence or young adulthood. A key finding is hypertension at a young age associated with suppressed renin and, frequently, hypokalemia with metabolic alkalosis or neuromuscular symptoms. Concurrent delayed puberty, absent development of secondary sexual characteristics or primary amenorrhea makes simple essential hypertension unlikely and requires targeted adrenal and endocrine evaluation.

In 46,XX individuals, the combination of primary amenorrhea, absent breast development and sparse pubic hair should raise suspicion of impaired sex steroid synthesis. When hypertension and hypokalemia are also present, 17α-hydroxylase deficiency becomes one of the most informative hypotheses because it unifies all findings within a single pathophysiological sequence. In 46,XY individuals, a female phenotype with an absent uterus or non-palpable gonads, particularly when associated with hypertension, strongly suggests a steroidogenic defect characterized by androgen deficiency and diversion toward mineralocorticoid production.

Suspicion should also be high in secondary hypertension with a biochemically discordant profile, such as aldosterone that is not elevated or appears normal despite markedly suppressed renin. In this setting, hypertension may be driven by excess deoxycorticosterone rather than classic primary aldosteronism. Similarly, the absence of hyperandrogenism, which is typical of some other forms of congenital adrenal hyperplasia, is a useful clue because steroidogenic flux is directed toward mineralocorticoids and corticosterone rather than androgens.

In internal medicine, the condition should be considered when hypokalemia is persistent or recurrent without an evident cause, particularly when associated with resistant hypertension. In gynecology, it should be included in the differential diagnosis of primary amenorrhea and absent pubertal maturation, especially when body hair is sparse and the gonadotropin profile suggests sex steroid deficiency. In pediatrics and adolescent medicine, suspicion is warranted in severe delayed puberty or a disorder of sex development accompanied by progressively developing hypertension.

Finally, clinical suspicion should initiate a diagnostic pathway that avoids common errors, including classifying the hypertension as essential, treating amenorrhea as dysfunctional without identifying its cause, or interpreting cortisol values that are not profoundly reduced as evidence against an adrenal defect. The key is the combination of clinical findings and the biochemical consistency of the steroidogenic diversion, which enables recognition of a rare but highly treatable condition when identified promptly.

Diagnosis of 17α-hydroxylase deficiency requires a multilevel approach that confirms the expected biochemical pattern, defines mineralocorticoid pathophysiology and documents impaired sex steroidogenesis, culminating in genetic confirmation. Initial assessment includes blood pressure, potassium and acid-base status because hypertension and hypokalemia are often the clinical entry points. Baseline endocrine evaluation should simultaneously include ACTH, morning cortisol and, most importantly, a steroid profile focused on the mineralocorticoid pathway and the precursors accumulating upstream of the enzymatic block.

A decisive step is characterization of the renin-angiotensin system. In mineralocorticoid excess caused by deoxycorticosterone, renin is typically suppressed and aldosterone is often low or inappropriately not elevated. Individual measurements may nevertheless be misleading, so interpretation should focus on the overall pattern and demonstration of excess non-aldosterone mineralocorticoid steroids. Concurrent assessment of sex steroids and androgen precursors typically shows low adrenal and gonadal androgen levels, with gonadotropins elevated relative to the phenotype and pubertal stage.

Diagnostic assessment of 17α-hydroxylase deficiency

• Confirmation of the mineralocorticoid phenotype: hypertension with suppressed renin, possible hypokalemia and findings consistent with mineralocorticoid excess not mediated by aldosterone.
• Targeted steroid profile: increased 11-deoxycorticosterone and corticosterone, reduced production of 17-hydroxylated steroids and androgen precursors, with the pattern more accurately defined by highly specific steroid panels.
• Assessment of the corticotropic axis: elevated ACTH with reduced or inappropriately normal cortisol; selected dynamic tests to document the steroidogenic block and functional glucocorticoid reserve.
• Etiological confirmation: molecular analysis of CYP17A1 to identify the pathogenic variant and support genetic counseling and phenotypic stratification.

After biochemical characterization, imaging has a complementary role. Abdominal ultrasonography or computed tomography may demonstrate adrenal hyperplasia, although absence of macroscopic hyperplasia does not exclude the diagnosis, particularly in partial forms or early disease. Pelvic imaging is often decisive for gonadal and genital assessment. In phenotypically female 46,XY individuals, absence of the uterus and ovaries and identification of ectopic gonads support a steroidogenic defect with undescended testes. In 46,XX individuals, evaluation of the uterus and ovaries helps quantify hypoestrogenism and plan replacement therapy and follow-up.

The differential diagnosis includes other causes of hyporeninemic hypertension and hypokalemia, such as primary aldosteronism, 11β-hydroxylase deficiency and apparent mineralocorticoid excess. 17α-hydroxylase deficiency is distinguished by the absence of hyperandrogenism and the characteristic pattern of sex steroid deficiency. Primary amenorrhea with sparse body hair and absent virilization in 46,XY individuals further supports the diagnosis. Chromosomal analysis may also be part of the evaluation in disorders of sex development because karyotype definition contributes to long-term clinical and psychological decisions.

A complete diagnosis also requires assessment of target-organ effects. This may include an electrocardiogram in patients with hypokalemia or palpitations, assessment of renal function and albuminuria in those with longstanding hypertension, and evaluation of skeletal risk in patients with prolonged hypogonadism. This step is not ancillary: it quantifies cumulative damage and establishes the baseline for targeted follow-up in which endocrine correction must proceed alongside prevention of cardiovascular and skeletal complications.

Classification of 17α-hydroxylase deficiency is useful because it links genotype, residual enzymatic function and clinical presentation. A first distinction separates forms with severe combined deficiency of 17α-hydroxylase and 17,20-lyase from partial forms in which residual activity partly preserves cortisol synthesis or sex steroid production. In classic forms, the pattern includes more frequent and marked hypertension, profound sex steroid deficiency and delayed diagnosis until puberty in 46,XX individuals. In partial forms, some patients retain a degree of estrogenization or limited androgen production, producing less distinct phenotypes and an increased risk of delayed diagnosis.

A second classification is phenotypic and depends on the karyotype and the trajectory of sex development. In 46,XX individuals, the condition generally presents as incomplete puberty with primary amenorrhea and sparse body hair. In 46,XY individuals, the spectrum ranges from a completely female phenotype with absent virilization to varying degrees of genital ambiguity, with markedly different clinical and decision-making implications. In this context, severity is not determined solely by steroid concentrations but also by the functional impact on identity, pubertal development, fertility and gonadal tumor risk in the presence of undescended gonads.

A practical marker of severity is the degree of mineralocorticoid excess. Patients may have moderate, controllable hypertension or resistant hypertension with substantial hypokalemia and a risk of cardiovascular complications. Duration of exposure is crucial: hypertension that remains undiagnosed for years may cause target-organ damage even after the endocrine disorder is corrected. Stratification should therefore include the estimated duration of disease, the blood pressure response to treatment and the presence of markers of vascular or renal damage.

A further classification axis concerns functional glucocorticoid reserve. Even though adrenal crises are uncommon, some patients may have an inadequate response to stress and require specific education and appropriately adjusted replacement therapy. Clinical severity is therefore multidimensional, involving blood pressure and potassium, pubertal development and reproductive function, and the ability to respond to stress. This approach prevents underestimation of the condition when the patient appears stable under baseline circumstances.

Finally, modern classification integrates genetic and clinical information, recognizing that some variants produce recurrent patterns in specific populations and that genotype-phenotype correlations, although imperfect, may guide prognosis and follow-up. Defining the clinical form is not merely descriptive: it determines the intensity of glucocorticoid treatment, antihypertensive strategies, methods of pubertal induction and reproductive planning, with a direct impact on long-term quality of life.

Treatment of 17α-hydroxylase deficiency has integrated goals: suppress excess ACTH and thereby reduce deoxycorticosterone production, correct hypertension and hypokalemia, and physiologically restore sex steroid function according to the patient’s karyotype, age and personal goals. Therapy must be individualized and monitored over time because achieving an appropriate balance between control of mineralocorticoid excess, prevention of glucocorticoid-related overtreatment and adequate sex steroid replacement requires progressive adjustment.

The endocrine cornerstone is glucocorticoid replacement at physiological doses, primarily intended to reduce ACTH and consequently the synthesis of 11-deoxycorticosterone and corticosterone. ACTH suppression improves blood pressure and facilitates potassium normalization, although the response may not be immediate and depends on disease duration and the degree of established cardiovascular remodeling. A central clinical objective is to avoid chronic overtreatment because excessive glucocorticoid exposure may cause weight gain, insulin resistance, osteopenia and deterioration of the cardiovascular risk profile, offsetting some of the benefits achieved through mineralocorticoid control.

Management of blood pressure and electrolytes may require additional targeted therapy. Mineralocorticoid receptor antagonists such as spironolactone or eplerenone are often useful for counteracting the effects of deoxycorticosterone and correcting hypokalemia. If hypertension persists, other antihypertensive medications may be added according to the patient’s clinical profile, with attention to comorbidities and arrhythmic risk in the presence of hypokalemia. Potassium supplementation may be temporarily required, but the primary objective is to remove the endocrine driver and block mineralocorticoid activity.

Sex steroid therapy is a cornerstone of long-term management. In 46,XX individuals, pubertal induction with estrogens, followed by progestogens when appropriate, aims to promote development of secondary sexual characteristics, support bone health and preserve psychophysical well-being. In 46,XY individuals, the strategy depends on the history of sex assignment, psychological context and shared decisions. If the patient was raised and lives as female, estrogen replacement is usually required. If virilization is desired, androgen therapy and selected surgical procedures may be considered within a multidisciplinary framework involving endocrinology, urology or gynecology, genetics and psychological support.

A specific issue concerns management of the gonads in 46,XY individuals with undescended testes. Intra-abdominal or ectopic gonads are associated with an increased long-term risk of local complications and gonadal neoplasia. Management may therefore include surveillance, surgical repositioning or removal according to age, risk profile, gender-related decisions and clinical feasibility. Decisions must be individualized and based on specialist assessment, avoiding automatic approaches and maintaining the patient’s overall well-being as the central objective.

Fertility is often impaired because of sex steroid deficiency and gonadal dysfunction, but counseling should be realistic and current. In 46,XX individuals with a uterus and adequate replacement therapy, selected assisted reproductive options may be considered. In 46,XY individuals, fertility is generally severely impaired. In all cases, discussion should include genetic counseling and evaluation of available options through a person-centered approach grounded in the actual clinical context.

Finally, treatment must include education regarding physiological stress and intercurrent illness. Although classic adrenal crisis is less common, patients with cortisol deficiency or chronic glucocorticoid therapy must understand when and how to increase the dose during fever, surgery or systemic stress and should have a written plan shared with their healthcare professionals. This aspect directly improves safety and reduces the risk of preventable adverse events.

Follow-up in 17α-hydroxylase deficiency should ensure hemodynamic stability, normalization of electrolytes, adequate suppression of ACTH without glucocorticoid excess and sex steroid replacement that appropriately supports pubertal development and long-term health. Assessments are more frequent during the initial titration phase, when blood pressure is stabilized and hypokalemia corrected, and may be spaced further apart once clinical and biochemical equilibrium has been achieved.

Laboratory monitoring includes electrolytes, renal function and targeted markers of steroidogenesis. Assessment of renin and mineralocorticoid-active steroid concentrations helps verify the effectiveness of ACTH suppression and guide antihypertensive management. With regard to glucocorticoid therapy, the goal is not to pursue a single basal cortisol value but to ensure adequate clinical control without signs of overtreatment and with sufficient protection during stress. Weight gain, hyperglycemia, skin fragility or worsening hypertension may suggest excessive glucocorticoid exposure, whereas marked fatigue or poor stress tolerance may indicate insufficient replacement.

Cardiovascular surveillance is central because hypertension may already have caused vascular remodeling. Blood pressure should be monitored through repeated measurements and, when indicated, instrumental assessment of target-organ damage, particularly in patients diagnosed late. Correction of hypokalemia must remain stable because fluctuations may predispose to neuromuscular symptoms and arrhythmias. In resistant hypertension, follow-up should include review of adherence, medication interactions and reassessment of endocrine control of the mineralocorticoid driver.

Pubertal and reproductive follow-up requires longitudinal assessment. In adolescent 46,XX individuals, estrogen titration and introduction of a progestogen should be adapted to somatic development, individual thrombotic risk, well-being and bone health goals. In 46,XY individuals, follow-up should integrate endocrinology and specialists in disorders of sex development, including gonadal assessment, management of gonadal risk and psychological support. In all patients, the quality of sex steroid replacement influences energy, body composition, mood and bone density, requiring an approach that does not reduce treatment to laboratory targets alone.

Skeletal health is a priority area of monitoring. Chronic hypogonadism reduces bone mass, making fracture risk assessment and, when appropriate, bone densitometry useful, particularly when diagnosis is delayed or additional risk factors are present. Adequate nutrition, physical activity compatible with cardiovascular status and correction of vitamin D deficiency when indicated are components of comprehensive follow-up.

Finally, follow-up should include continuing education and planning for intercurrent illness. Patients must understand the need to adjust glucocorticoid therapy during physiological stress and should have a shared care plan with their healthcare professionals. Continuity of care is particularly important during transitions, including the move from pediatric to adult services, because these periods may increase the risk of therapeutic errors, loss to follow-up and recurrence of hypertension and hypokalemia.

The prognosis of 17α-hydroxylase deficiency is generally favorable when the diagnosis is made promptly and treatment is appropriately individualized. Control of ACTH with glucocorticoids and management of mineralocorticoid excess usually stabilize blood pressure and electrolyte levels, reducing long-term cardiovascular risk. Prognosis nevertheless depends substantially on the duration of hypertension and hypokalemia before diagnosis and on the quality of follow-up because target-organ damage caused by chronic hypertension may not be fully reversible.

The most clinically relevant complications are cardiovascular and renal. Persistent or late-treated hypertension may predispose to left ventricular hypertrophy, arterial stiffness and an increased long-term risk of cerebrovascular events. Hypokalemia may cause weakness, cramps and, in severe cases, susceptibility to arrhythmias, particularly when additional predisposing factors or medications affecting repolarization are present. Stable potassium control and correction of the mineralocorticoid driver significantly reduce these risks but require continuous monitoring.

A second group of complications is related to hypogonadism and sex steroid deficiency. Reduced bone mass, osteopenia or osteoporosis may increase fracture risk, particularly when puberty is not appropriately induced or replacement therapy is inconsistent. Quality of life may be impaired by fatigue, reduced muscle mass and neuropsychological symptoms associated with hypoestrogenism or hypotestosteronism, requiring an approach that addresses overall well-being rather than endocrine measurements alone.

Fertility is frequently impaired. Even when endocrine correction is effective, gonadal function may remain compromised and reproductive options require specialist evaluation. Reproductive prognosis is therefore variable and depends on anatomy, response to replacement therapy, age at diagnosis and individual goals. In parallel, 46,XY individuals with undescended gonads have a long-term risk of gonadal complications that requires surveillance or surgical management according to specialist assessment.

The principal treatment-related complication is chronic glucocorticoid overtreatment, which increases metabolic risk, adversely affects body composition and reduces bone mass. Structured follow-up must therefore balance sufficient ACTH suppression to control deoxycorticosterone production against minimization of excessive glucocorticoid exposure. Antihypertensive treatment and mineralocorticoid receptor antagonists may also cause specific adverse effects that should be prevented and monitored systematically.

Overall, with accurate diagnosis and continuity of care, patients can achieve durable clinical stability. The best outcomes are obtained when the condition is recognized before hypertension has caused cumulative damage and when sex steroid replacement is introduced physiologically and monitored over time, with attention to cardiovascular, skeletal and psychological health. The practical objective is to transform a rare and complex condition into a manageable chronic care pathway, reducing preventable complications and substantially improving long-term outcomes.

• Cardiovascular complications caused by mineralocorticoid hypertension: left ventricular hypertrophy, arterial stiffness and target-organ damage caused by prolonged hypertension.
• Electrolyte complications: hypokalemia with weakness, cramps and susceptibility to arrhythmias, particularly during physiological stress or with interfering therapies.
• Skeletal complications: reduced bone mass and increased fracture risk caused by prolonged hypogonadism and possible iatrogenic glucocorticoid excess.
• Reproductive and gonadal complications: frequent infertility, need for dedicated counseling and, in individuals with undescended gonads, an increased long-term risk of gonadal complications.
• Iatrogenic complications: chronic glucocorticoid overtreatment with metabolic and skeletal risks, and adverse effects of antihypertensive medications or mineralocorticoid receptor antagonists.