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Late-Onset Congenital Adrenal Hyperplasia (LOCAH/NCCAH)

A non-classic, milder form of 21-hydroxylase deficiency presenting in adolescence or adulthood.

Written by: Saygı Hospital Health Guide Editorial Board
Published:

This content is for general information; please consult your physician for diagnosis and treatment.

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What is Late-Onset Congenital Adrenal Hyperplasia (LOCAH/NCCAH)?

Late-onset CAH (also called non-classic CAH, NCCAH) results from mild mutations in the CYP21A2 gene with 20–60% residual 21-hydroxylase activity. Cortisol synthesis is mildly impaired, ACTH rises, and excess 17-hydroxyprogesterone is shunted toward androgen pathways.

Prevalence varies by ethnicity (1:50–1:1000), with higher rates in Ashkenazi Jews, Mediterranean, and Middle Eastern populations. Many cases overlap with polycystic ovary syndrome (PCOS).

Diagnosis is based on early-morning 17-hydroxyprogesterone (>2 ng/mL screen, >10 ng/mL diagnostic) and ACTH stimulation test (post-stim 17-OHP >10–15 ng/mL); CYP21A2 sequencing confirms genotype.

Symptoms

Premature pubarche in children
Acne, hirsutism, frontal hair thinning in adolescents and women
Menstrual irregularity, oligomenorrhea, anovulatory infertility
Tall childhood stature with advanced bone age and reduced final height
Polycystic ovaries on imaging (overlap with PCOS)
Generally no salt-wasting and normal cortisol response in basal state

Risk Factors

Autosomal recessive inheritance — both CYP21A2 alleles affected
Family history of NCCAH or classic CAH
Ashkenazi Jewish, Mediterranean, Middle Eastern, Hispanic ancestry
Carrier parents identified through genetic screening
Symptoms triggered or worsened by puberty, weight gain, stress

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • Premature pubic hair, axillary hair, or rapid bone-age advance in childhood
  • New-onset hirsutism, treatment-resistant acne, or menstrual irregularity
  • Unexplained infertility or recurrent miscarriage
  • Family member diagnosed with classic or non-classic CAH

Treatment Methods

01
Often no treatment in asymptomatic adults — surveillance only
02
Hydrocortisone or low-dose prednisone/dexamethasone for symptomatic hyperandrogenism or fertility
03
Combined oral contraceptive ± antiandrogen (spironolactone) for hirsutism in non-fertility-seeking women
04
Stress-dose glucocorticoids for major surgery or severe illness in those on therapy
05
Preconception counseling and consider partner screening for classic CAH (CYP21A2)
06
Long-term endocrinology follow-up to balance androgen control vs. iatrogenic Cushing risk
07
Bone health and metabolic monitoring

Which Department to Visit?

You can visit our Endokrinoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.