Whitaker Syndrome - Causes, Clinical Features, Diagnosis, and Management

Introduction:

The autoimmune polyglandular syndromes are groups of hormone-related disorders that appear in specific patterns in people with immune system issues. These syndromes can be treated and monitored for other hormone problems that might develop. Three main types are recognized: APS1, APS2, and APS3, along with a sporadic X-linked syndrome involving immune system dysregulation, multiple hormone issues, and gut problems. Another category is emerging in cancer patients treated with immune-regulating drugs, where the drugs help the immune system target tumor cells. Still, it may also trigger autoimmune reactions against hormone-producing organs.

What Is Autoimmune Polyglandular Syndrome Type 1?

Polyglandular autoimmune syndrome (PGA-I) is a rare condition that can be inherited sporadically or through autosomal recessive genes.

It involves three main health issues, which include:

• Chronic mucocutaneous candidiasis (chronic yeast infections affecting skin and mucous membranes).

• Hypoparathyroidism (underactive parathyroid glands).

• Autoimmune adrenal insufficiency (adrenal glands not producing enough hormones).

The first symptoms usually appear in childhood, and the three main diseases develop within the first 20 years of life. Additional conditions can continue to emerge until at least the age of 50. Candidiasis is usually the first symptom in children under five years old. Hypoparathyroidism follows, usually in children under ten years old. Finally, Addison's disease occurs in children under 15 years old.

What Are the Causes of Autoimmune Polyglandular Syndrome Type 1?

Autoimmunity in APS-1 is caused by mutations in the AIRE (autoimmune regulator) gene on chromosome 21q22.3. Normally, this gene helps the thymus display various body-specific antigens, so developing T-cells that strongly react to these antigens are eliminated, preventing autoimmunity. APS-1 is usually inherited as an autosomal recessive disorder. However, point mutations can cause an autosomal dominant form, which seems less severe. This suggests that AIRE mutations might be more common in other immune disorders not previously linked to these mutations.

Initially, the cause of mucocutaneous candidiasis in these patients was unknown and not linked to autoimmune issues. Recent studies have shown that problems with T helper-17 (Th-17) cells, which are part of the immune system's response to fungi, cause chronic mucocutaneous candidiasis (CMC). Patients with APS type 1 produce autoantibodies against Th-17 cell cytokines, mainly IL-17A, IL-17F, and IL-22, disrupting their body's natural antifungal defenses.

What Are the Clinical Manifestations of Autoimmune Polyglandular Syndrome Type 1?

The three main classical features seen in APS1 are mentioned below:

• Mucocutaneous Candidiasis: This involves chronic fungal infections of the skin and mucous membranes.

• Hypoparathyroidism: This condition leads to low calcium and phosphate levels in the blood and low parathyroid hormone (PTH) concentrations.

• Addison's Disease: This results in cortisol deficiency, sometimes aldosterone deficiency, and high levels of adrenocorticotropic hormone (ACTH).

  • Symptoms include hyperpigmentation, abdominal pain, vomiting, weight loss, electrolyte imbalances, and fasting-induced hypoglycemia.

To diagnose APS1, at least two of these three classical features must be present.

Other Clinical Manifestations -

Whitaker syndrome can also include other symptoms, such as:

• Periodic rash with fever.

• Kerato-conjunctivitis.

• Chronic diarrhea.

• Primary gonadal failure usually occurs before or after puberty.

• Hashimoto thyroiditis, which leads to hypothyroidism.

• Vitamin B12 deficiency.

• Chronic active hepatitis.

• Type 1 diabetes mellitus (T1DM).

Ectodermal Dystrophy: This includes enamel hypoplasia affecting only permanent teeth, pitted nail dystrophy not related to fungal infections, and visible changes in the eardrums due to calcium deposits. That is why APS1 also includes the term APECED (Autoimmune Poly Endocrinopathy, Candidiasis, Ectodermal Dystrophy)

Other reported features include iritis, optic atrophy, skin changes called keratopathy, alopecia, and vitiligo.

What Are the Clinical Findings Regarding Polyglandular Autoimmune Syndrome Type 1?

• Ovarian failure affects about 60 percent of females with APS1, while testicular failure occurs in only about 15 percent of males.

• Parietal cell atrophy with atrophic gastritis and B12 deficiency, as well as type 1 diabetes mellitus (T1DM), affects about 12 percent of patients, with diabetes being a later complication compared to early parathyroid and adrenal deficiencies.

• Although anti-thyroid antibodies are common, hypothyroidism develops in only about 5 of patients.

• Rare symptoms include diabetes insipidus, growth hormone deficiency due to hypophysitis, infertility caused by sperm antibodies in males, and ovarian failure in females.

• In APS1, symptoms typically appear earlier and are more severe than in type 2 autoimmune polyglandular syndrome (APS2).

Most patients with APS1 show symptoms by the age of 5. In about 75 percent of cases, non-endocrine symptoms appear before endocrine symptoms. The first manifestations are often:

1. Mucocutaneous Candidiasis: Presenting in about 60 percent of cases.

2. Malabsorption: Seen in about 10 percent of cases.

3. Vitiligo, Alopecia, Hepatitis, and Keratopathy: Each occurring in about 5 percent of affected individuals.

How Can Autoimmune Polyglandular Syndrome Type 1 Be Diagnosed?

The diagnosis of APS type 1 mostly relies on testing for specific autoantibodies in the blood. This is performed in patients who show symptoms of one or more endocrine disorders or chronic mucocutaneous candidiasis. A conclusive diagnosis can be confirmed by analyzing DNA for mutations in the AIRE gene, which can be helpful for patients who do not initially meet the criteria for APS type 1.

Serum Endocrine Autoantibody Screening-

This screening helps confirm the autoimmune nature of the disease and identifies patients who might develop multiple endocrine deficiencies in the future. It's also useful for screening family members who may be at risk.

The panel may include some autoantibodies to:

• 21-hydroxylase.

• 17-hydroxylase.

• Thyroid peroxidase (TPO).

• Thyroid-stimulating immunoglobulins (TSI).

• Glutamic acid decarboxylase.

• Islet cell antibodies.

• Parietal cell enzyme antibodies.

Not all patients have positive antibodies, so their absence does not rule out PGA-I.

End-Organ Function Tests -

End-organ function test will help confirm the diagnosis of autoimmune polyglandular syndrome

• In males, test testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH).

• No lab assessment of the gonadotropin axis is needed in females with regular menses. Check estradiol, FSH, LH, and prolactin levels for irregular or absent menses.

• Thyroid-stimulating hormone (TSH) and, if needed, free thyroxine (T4) and free triiodothyronine (T3) - TSH may be elevated, and free T4 and T3 may be low.

• Plasma renin activity - High levels may be noted.

• Electrolytes, albumin, and fasting blood glucose - The values of calcium, phosphorus, and magnesium vary depending on the patient’s condition and the severity and duration of the illness. Hypoparathyroidism causes low calcium, elevated phosphorus, and low magnesium.

Additional Tests -

• Fungal skin scrapings may test positive for candidiasis.

• Complete blood count (CBC) with mean cell volume (MCV) and vitamin B-12 levels - These may show lymphocytosis, neutropenia, and anemia. If pernicious anemia is present, MCV is elevated, and vitamin B-12 levels are low.

What Is the Treatment for Whitaker Syndrome?

Treatment guidelines for polyglandular autoimmune syndromes include immune suppression and modulation using agents such as:

• Glucocorticoids like Prednisone.

• Cyclosporin,

• Calcineurin inhibitors like Tacrolimus and Sirolimus.

• Methotrexate.

• Mycophenolate mofetil.

• Rituximab (a CD20 inhibitor)

These treatments are particularly used for autoimmune hepatitis, enteropathy, tubulo-interstitial nephritis, interstitial lung disease, and keratoconjunctivitis.

General Management:

Common steps involved in management include

• Hormonal Replacement Therapy: Replace deficient hormones and vitamins (such as vitamin D and B12) as needed.

• Monitoring: Regularly screen for other potential deficiencies, especially in patients with circulating antibodies for adrenal steroidogenesis components, thyroid (TPO, TG antibodies), and calcium, phosphate, or parathyroid hormone levels.

• Conduct periodic assessments of HbA1c (glycated hemoglobin), fasting glucose, and liver function (ALT and AST) at six months to one-year intervals.

Specific Management:

• Screening for Adrenal Insufficiency: For patients with initial manifestations like hypoparathyroidism and chronic mucocutaneous candidiasis, screen for primary adrenal insufficiency via an afternoon ACTH concentration every six months and at least annually. An ACTH level over 80 pg/ml (picograms per milliliter) is highly suggestive, and over 100 pg/ml is virtually diagnostic.

• ACTH-Stimulation Test: Some recommend an ACTH-stimulation test to document adrenal reserve, while others suggest starting cortisol replacement therapy and monitoring sodium and potassium levels to exclude evolving aldosterone deficiency, as well as checking supine and standing blood pressure.

• Anti-Candida Drugs: When using anti-candida drugs like Ketoconazole, be cautious as these can interfere with cortisol synthesis and potentially worsen adrenal insufficiency.

• Cortisol Replacement Therapy:

  • Initially, cortisol should be given in a stress dosage (commonly two to three times the daily maintenance dose of 10 milligrams per square meter per day) for several days after the initial diagnosis.

  • Afterward, administer normal replacement doses of 8 to 10 mg/m²/day in 3 divided oral doses daily.

• Administer Hydrocortisone via intravenous or intramuscular injection if oral absorption is impaired due to candidiasis in the esophagus or lower GI (gastrointestinal) tract.

Conclusion

Autoimmune polyglandular syndrome type 1 is a complicated condition that requires a thorough and team-based management approach. Early diagnosis, careful monitoring, and specific treatments are key to reducing the syndrome's effects and improving outcomes. Ongoing research and medical advancements bring hope for better treatments and a higher quality of life for those with Whitaker Syndrome.