17 20 Lyase Deficiency Isolated C3277849
A rare enzymatic disorder affecting sex hormone production. Impairs development of sexual characteristics in both males and females. Treatment involves hormone supplementation.
Key facts at a glance
- ICD-10
- E34.9
- ICD-11
- 5A00.0
- Body system
- endocrine
- Severity
- severe
- Chronic
- true
Signs and symptoms
Common signs and symptoms that may indicate this condition.
Warning signs - seek immediate care
Hypertension
Elevated blood pressure due to accumulation of mineralocorticoids (deoxycorticosterone) that causes sodium and water retention.
Seek immediate medical attention if blood pressure is significantly elevated or accompanied by headache, vision changes, or chest pain.
Ambiguous genitalia
(genitourinary)In genetic males (46,XY), undervirilization of external genitalia including micropenis, hypospadias, and incomplete male external genitalia development.
Frequency: 90-95% of male patients
Primary amenorrhea
(reproductive)In genetic females (46,XX), absence of menstrual periods by age 15 or after 3 years of no menstruation following breast development.
Frequency: 90-95% of female patients
Delayed puberty
(endocrine)Failure to enter puberty at the expected age, with absent or minimal development of secondary sexual characteristics.
Frequency: 85-90% of patients
Absent secondary sexual characteristics
(endocrine)Lack of development of breasts, body hair, voice changes, and other sex-specific physical changes expected during puberty.
Frequency: 80-90% of patients
Infertility
(reproductive)Inability to conceive naturally due to inadequate sex hormone production affecting gamete function and reproductive organ development.
Frequency: 70-80% of adult patients
Fatigue
(constitutional)Persistent tiredness and lack of energy related to hormonal imbalances and altered steroid metabolism.
Frequency: 30-50% of patients
Orthostatic hypotension
(cardiovascular)Drop in blood pressure upon standing, possibly related to volume depletion or autonomic nervous system effects from steroid imbalances.
Frequency: 10-20% of patients
Diagnosis and tests
How this condition is diagnosed and what test results mean.
Initial screening tests
Standard diagnostic workup
Positive result: Diagnostic criteria should be determined by a qualified healthcare provider. [Content pending medical review.]
Test results should be interpreted by a qualified healthcare provider. [Content pending medical review.]
Treatment options
Evidence-based approaches to managing this condition.
First-line treatments
Endocrine management
Active treatment with regular monitoring by a healthcare provider is recommended.
Targeted Androgen Replacement
Testosterone replacement therapy for patients with androgen deficiency, dosed according to residual enzymatic activity and desired pubertal development goals.
Glucocorticoid Suppression Therapy
Low-dose glucocorticoids may be used to suppress ACTH-driven androgen excess in certain presentations, with careful monitoring for side effects.
Additional treatment options
Androgen Level and Gonadal Function Surveillance
Regular monitoring of testosterone, DHEA, and gonadotropin levels to guide replacement therapy and assess testicular function.
monitoringIdentity and Fertility Counseling
Psychological support addressing challenges specific to isolated 17,20-lyase deficiency including fertility concerns, identity development, and disclosure decisions.
psychologicalFertility Assistance Consultation
Early consultation with reproductive endocrinology specialists to explore fertility preservation options and assisted reproductive technologies when indicated.
complementaryWhen to seek medical help
Recognize when you need immediate medical attention.
See a doctor within 24 hours
Moderate to severe symptoms that may indicate worsening of this condition. Prompt medical evaluation is recommended.
Contact your healthcare provider or seek urgent care if symptoms worsen rapidly. Go to the emergency department for life-threatening symptoms.
Frequently asked questions
Common questions about this topic.
What is 17 20 Lyase Deficiency Isolated C3277849?
Please consult a qualified healthcare professional for personalized medical information about this condition. [Content pending medical review.]
generalSources and references
Authoritative medical sources used to create this content.
Miller WL, Auchus RJ. The molecular biology, biochemistry, and physiology of human steroidogenesis and its disorders. Endocr Rev. 2011;32(1):81-151.
Speiser PW, Arlt W, Auchus RJ, et al. Congenital Adrenal Hyperplasia Due to Steroid 21-Hydroxylase Deficiency: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(11):4043-4088.
Miller WL. Disorders in the initial steps of steroid hormone synthesis. J Steroid Biochem Mol Biol. 2017;165(Pt A):18-37.
Auchus RJ, Miller WL. Molecular modeling of human CYP17A1: insights into the structural basis of 17,20-lyase deficiency. Ann N Y Acad Sci. 2012;1240:44-47.
Melmed S, Polonsky KS, Larsen PR, Kronenberg HM. Williams Textbook of Endocrinology. 14th ed. Elsevier; 2019.
Kumar R, Tena-Sempere M, editors. Endocrinology: Adult and Pediatric. 7th ed. Elsevier; 2016.
Gidlöf S, Falhammar H, Thilén A, et al. One hundred years of congenital adrenal hyperplasia in Sweden: a retrospective, population-based cohort study. Lancet Diabetes Endocrinol. 2013;1(1):35-42.
Endocrine Society. Congenital Adrenal Hyperplasia: Clinical Practice Guidelines. J Clin Endocrinol Metab. 2018;103(11):4043-4088.
Medication Comparisons
Compare medications used to treat 17 20 Lyase Deficiency Isolated C3277849. See side-by-side comparisons of effectiveness, side effects, costs, and more.
View Medication ComparisonsThis information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 26, 2026. · Read our editorial policy