Skip to content
How It Works
Explore
Resources Ask a Question
Who It's For
Patients
Decode results, prep for appointments, weigh options.
Caregivers & advocates
Carry the research load for someone you love.
Providers & clinicians
Resources for patients in your practice.
Log In Ask a Question
PubMed This is a summary of 22 peer-reviewed journal articles Updated
Endocrinology · Simple Virilizing Congenital Adrenal Hyperplasia

Understanding the Diagnosis: Classic CAH, Simple Virilizing Form

At a Glance

Simple virilizing congenital adrenal hyperplasia (SV-CAH) is a genetic condition where the adrenal glands lack enough enzyme to make cortisol, leading to excess male hormones. With daily hormone replacement medication and strict sick day rules, people with SV-CAH can live healthy, active lives.

Receiving a diagnosis of Congenital Adrenal Hyperplasia (CAH) can feel overwhelming, but understanding the specific “simple virilizing” form can help you manage the condition effectively. CAH is a genetic disorder that affects the adrenal glands, which sit on top of the kidneys and produce essential hormones [1][2].

In the Simple Virilizing (SV) form, the body has a partial deficiency of an enzyme called 21-hydroxylase. This enzyme is needed to make cortisol (the “stress hormone”) and aldosterone (the hormone that balances salt and water) [1][3].

The CAH Spectrum

CAH is often described as a spectrum based on how much enzyme activity remains.

Feature Salt-Wasting (SW) Simple Virilizing (SV) Non-Classic (NC)
Enzyme Activity 0-1% [4] 1-2% [4] 20-60% [4]
Cortisol Production Deficient Deficient Normal or slightly low
Aldosterone Production Deficient (life-threatening without meds) Sufficient to prevent daily crises Normal
Typical Diagnosis At birth / Newborn screening At birth (females) / Early childhood (males) Childhood / Adulthood
  • Salt-Wasting (SW) CAH: The most severe form, where there is little to no enzyme activity. These patients cannot retain salt, which can lead to life-threatening emergencies early in life [5][6].
  • Simple Virilizing (SV) CAH: This is the middle of the spectrum. The body retains enough enzyme activity (typically 1–2%) to produce just enough aldosterone to prevent a “salt-wasting crisis,” but it still cannot make enough cortisol [1][3].
  • Non-Classic (NC) CAH: The mildest form, often diagnosed later in childhood or adulthood, usually presenting with symptoms related to excess hormones like acne or early puberty [7][1].

Why “Simple Virilizing”?

The term virilization refers to the development of male-typical physical characteristics. Because the “pathway” to make cortisol is blocked, the adrenal glands overproduce other hormones called androgens (male-type sex hormones like testosterone) [2][8].

  • In Female Newborns: High levels of androgens before birth can cause the external genitalia to look different (atypical or ambiguous), which often leads to an early diagnosis [8][9].
  • In Male Newborns: Because boys already have male-typical genitalia, SV-CAH may not be noticed at birth. Without newborn screening, these boys might be diagnosed later when they show signs of early puberty (such as pubic hair or rapid growth) [10][11].

Diagnosis and Monitoring

Most cases are now caught through newborn screening, which checks levels of a hormone called 17-hydroxyprogesterone (17-OHP) [11][12]. Doctors also use genetic testing (mutational analysis) to confirm the diagnosis and help predict the clinical form [13][14].

Management involves glucocorticoid replacement therapy to replace the missing cortisol [15]. Because the goal is to balance hormone levels, doctors carefully monitor:

  • Growth Velocity: Ensuring the child is growing at a healthy rate [16].
  • Bone Age: Using X-rays to ensure the bones aren’t maturing too quickly due to androgen excess [16].
  • Hormone Levels: Serial blood tests for 17-OHP and androstenedione [17][18].

Life with SV-CAH

With consistent treatment, the prognosis for individuals with SV-CAH is generally excellent [10]. While patients must take medication daily and follow “sick day rules”—increasing the dose during illness to prevent an adrenal crisis—they can lead full, active lives [19][20].

Adults may face specific challenges, such as monitoring for Testicular Adrenal Rest Tumors (TARTs) in men or managing fertility in women, but specialized endocrine care can address these concerns [21][22]. Early diagnosis through screening has significantly improved the long-term health and growth outcomes for children born with this condition [10][11].

Common questions in this guide

What is simple virilizing CAH?
Simple virilizing CAH is a genetic disorder where the body makes too little cortisol and too many androgens, but enough aldosterone to prevent severe salt loss. It is caused by a partial deficiency of the 21-hydroxylase enzyme.
How is simple virilizing CAH diagnosed?
Most cases are diagnosed shortly after birth through newborn screening, which checks for high levels of the hormone 17-OHP. Doctors may also use genetic testing to confirm the specific type of CAH.
What are the sick day rules for CAH?
Sick day rules are guidelines for increasing a patient's glucocorticoid medication during times of illness, surgery, or major stress. This prevents a potentially life-threatening adrenal crisis when the body cannot naturally produce enough stress hormones.
How does SV-CAH affect growth and development?
Without proper treatment, excess androgens can cause rapid childhood growth and early puberty, but may cause the growth plates to close prematurely. Endocrinologists monitor bone age and growth velocity to ensure medication doses are correctly balanced.
Why do men with SV-CAH need scrotal ultrasounds?
Adult males with CAH are at risk for developing testicular adrenal rest tumors (TARTs). Regular scrotal ultrasounds help detect these benign tumors early so they can be managed to protect fertility.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Is my child's current 17-OHP level within the target range for the simple virilizing form?
  2. 2.What is our specific 'sick day rule' protocol for increasing medication during illness or stress?
  3. 3.How will you monitor my child's growth and bone age to ensure the medication dose is balanced?
  4. 4.Do we need to carry an emergency hydrocortisone injection kit, and can you train us on how to use it?
  5. 5.(For adult males) When should we start regular scrotal ultrasounds to check for adrenal rest tumors?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (22)
  1. 1

    Genetic characterization of a large cohort of Argentine 21-hydroxylase Deficiency.

    Fernández CS, Taboas M, Bruque CD, et al.

    Clinical endocrinology 2020; (93(1)):19-27 doi:10.1111/cen.14190.

    PMID: 32289882
  2. 2

    The spectrum of CYP21A2 gene mutations in patients with classic salt wasting form of 2l-hydroxylase deficiency in a Chinese cohort.

    Liu Y, Zheng J, Liu N, et al.

    Molecular genetics & genomic medicine 2020; (8(11)):e1501 doi:10.1002/mgg3.1501.

    PMID: 32959514
  3. 3

    Clinical Role of CYP2C19 Polymorphisms in Patients with Congenital Adrenal Hyperplasia Due to 21-hydroxylase Deficiency.

    Grošelj U, Žerjav Tanšek M, Trebušak Podkrajšek K, et al.

    Acta chimica Slovenica 2016; (63(1)):33-7 doi:10.17344/acsi.2015.1797.

    PMID: 26970786
  4. 4

    Genetic Characterization of a Cohort of Italian Patients with Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency.

    Concolino P, Perrucci A, Carrozza C, Urbani A

    Molecular diagnosis & therapy 2023; (27(5)):621-630 doi:10.1007/s40291-023-00666-x.

    PMID: 37548905
  5. 5

    Detection of a novel severe mutation affecting the CYP21A2 gene in a Chilean male with salt wasting congenital adrenal hyperplasia.

    Arteaga E, Valenzuela F, Lagos CF, et al.

    Endocrine 2020; (67(1)):258-263 doi:10.1007/s12020-019-02097-3.

    PMID: 31571129
  6. 6

    Molecular Analysis of 21-Hydroxylase Deficiency Reveals Two Novel Severe Genotypes in Affected Newborns.

    Concolino P, Paragliola RM

    Molecular diagnosis & therapy 2021; (25(3)):327-337 doi:10.1007/s40291-021-00520-y.

    PMID: 33710594
  7. 7

    Non-classical congenital adrenal hyperplasia: current insights into clinical implications, diagnosis and treatment.

    Loli P, Menotti S, di Filippo L, Giustina A

    Endocrine 2025; (90(1)):1-16 doi:10.1007/s12020-025-04341-5.

    PMID: 40699527
  8. 8

    Antenatal Diagnosis and Treatment in Congenital Adrenal Hyperplasia Due to 21-hydroxylase Deficiency and Congenital Adrenal Hyperplasia Screening in Newborns

    Yavaş Abalı Z, Kurnaz E, Güran T

    Journal of clinical research in pediatric endocrinology 2025; (17(Suppl 1)):33-43 doi:10.4274/jcrpe.galenos.2024.2024-6-10-S.

    PMID: 39713885
  9. 9

    How the Child's Gender Matters for Families Having a Child With Congenital Adrenal Hyperplasia.

    Fleming L, Knafl K, Van Riper M

    Journal of family nursing 2017; (23(4)):516-533 doi:10.1177/1074840717735499.

    PMID: 29046104
  10. 10

    Impact of Newborn Screening on Adult Height in Patients With Congenital Adrenal Hyperplasia (CAH).

    Hoyer-Kuhn H, Eckert AJ, Binder G, et al.

    The Journal of clinical endocrinology and metabolism 2023; (108(11)):e1199-e1204 doi:10.1210/clinem/dgad307.

    PMID: 37256841
  11. 11

    Evaluation of the Dutch neonatal screening for congenital adrenal hyperplasia.

    van der Linde AAA, Schönbeck Y, van der Kamp HJ, et al.

    Archives of disease in childhood 2019; (104(7)):653-657 doi:10.1136/archdischild-2018-315972.

    PMID: 30712004
  12. 12

    Newborn Screening for CAH-Challenges and Opportunities.

    Heather NL, Nordenstrom A

    International journal of neonatal screening 2021; (7(1)) doi:10.3390/ijns7010011.

    PMID: 33668620
  13. 13

    Issues with the Detection of Large Genomic Rearrangements in Molecular Diagnosis of 21-Hydroxylase Deficiency.

    Concolino P

    Molecular diagnosis & therapy 2019; (23(5)):563-567 doi:10.1007/s40291-019-00415-z.

    PMID: 31317337
  14. 14

    Rare nonclassic type of Congenital adrenal hyperplasia due to 21-hydroxylase deficiency and genotype-phenotypic correlation.

    Hou Y, Li Y, Ai J, Tian L

    Heliyon 2024; (10(5)):e27042 doi:10.1016/j.heliyon.2024.e27042.

    PMID: 38439885
  15. 15

    Mortality in children with classic congenital adrenal hyperplasia and 21-hydroxylase deficiency (CAH) in Germany.

    Dörr HG, Wollmann HA, Hauffa BP, et al.

    BMC endocrine disorders 2018; (18(1)):37 doi:10.1186/s12902-018-0263-1.

    PMID: 29884168
  16. 16

    The utility of annual growth velocity standard deviation scores and measurements of biochemical parameters in long-term treatment monitoring of children with 21-hydroxylase deficiency.

    Ozdemir Dilek S, Turan I, Gurbuz F, et al.

    Hormones (Athens, Greece) 2022; (21(3)):391-397 doi:10.1007/s42000-022-00354-1.

    PMID: 35243601
  17. 17

    Salivary 17-Hydroxyprogesterone Levels in Children with Congenital Adrenal Hyperplasia: A Retrospective Longitudinal Study Considering Auxological Parameters.

    Dubinski I, Bechtold S, Bidlingmaier M, et al.

    Hormone research in paediatrics 2023; (96(3)):259-266 doi:10.1159/000526485.

    PMID: 35960318
  18. 18

    A 4-hour Profile of 17-hydroxyprogesterone in Salt-wasting Congenital Adrenal Hyperplasia: Is the Serial Monitoring Strategy Worth the Effort?

    Besci Ö, Erbaş İM, Küme T, et al.

    Journal of clinical research in pediatric endocrinology 2022; (14(2)):145-152 doi:10.4274/jcrpe.galenos.2021.2021-9-17.

    PMID: 34866371
  19. 19

    Treatment and Prevention of Adrenal Crisis and Family Education

    Çamtosun E, Sangün Ö

    Journal of clinical research in pediatric endocrinology 2025; (17(Suppl 1)):80-92 doi:10.4274/jcrpe.galenos.2024.2024-6-12-S.

    PMID: 39713905
  20. 20

    Adrenal insufficiency.

    Husebye ES, Pearce SH, Krone NP, Kämpe O

    Lancet (London, England) 2021; (397(10274)):613-629 doi:10.1016/S0140-6736(21)00136-7.

    PMID: 33484633
  21. 21

    Experience in optimizing fertility outcomes in men with congenital adrenal hyperplasia due to 21 hydroxylase deficiency.

    King TF, Lee MC, Williamson EE, Conway GS

    Clinical endocrinology 2016; (84(6)):830-6 doi:10.1111/cen.13001.

    PMID: 26666213
  22. 22

    The impact of CYP21A2 (P30L/I172N) genotype on female fertility in one family.

    Kocova M, Anastasovska V, Bitovska I

    European journal of medical research 2019; (24(1)):21 doi:10.1186/s40001-019-0379-4.

    PMID: 31217034

This page provides educational information about Simple Virilizing CAH. Always consult your endocrinologist or pediatric specialist regarding hormone replacement and sick day rules.

Get notified when new evidence is published on Classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency, simple virilizing form.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.