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Zollinger‑Ellison Hereditary Syndrome (ZEHS)

Overview

Zollinger‑Ellison hereditary syndrome (ZEHS) is a rare, autosomal‑dominant genetic disorder that predisposes affected individuals to develop multiple gastrin‑producing neuroendocrine tumors (gastrinomas) of the pancreas and duodenum, as well as various other endocrine neoplasias. The syndrome is the hereditary form of the more commonly known Zollinger‑Ellison syndrome (ZES), which can also occur sporadically.

Who it affects: Both males and females are equally susceptible. The condition usually manifests in the second or third decade of life, but penetrance is variable—some carriers remain asymptomatic into adulthood.

Prevalence: ZEHS accounts for roughly 20–25 % of all gastrinomas and is the most frequent hereditary cause of ZES. The overall prevalence of ZEHS is estimated at 1–2 per 100,000 individuals worldwide <sup>[1]</sup>. Because it is linked to the multiple endocrine neoplasia type 1 (MEN‑1) gene mutation, families with MEN‑1 have a 30–50 % chance of carrying ZEHS.

Symptoms

Symptoms result from excessive gastric acid secretion and from the mass effect of gastrinomas. Not all patients experience every symptom, and the severity can vary widely.

Gastro‑intestinal symptoms

• Refractory peptic ulcer disease – ulcers that persist despite standard proton‑pump inhibitor (PPI) therapy.
• Abdominal pain – usually epigastric, worsening after meals.
• Diarrhea – acid overload irritates the intestine, leading to watery stools; can be severe enough to cause dehydration.
• Steatorrhea (fatty stools) – malabsorption from acid‑induced pancreatic enzyme inactivation.
• Nausea & vomiting – especially after large meals.

Systemic and endocrine symptoms

• Weight loss – due to chronic malabsorption and decreased appetite.
• Gastro‑esophageal reflux disease (GERD) – acid reflux is common.
• Hypocalcemia – secondary to acid‑induced calcium loss.
• Hyperparathyroidism – when ZEHS occurs as part of MEN‑1, leading to elevated calcium levels.
• Pituitary tumors – another MEN‑1 manifestation; may cause headaches, visual changes, or hormone excess.

Symptoms related to tumor spread

• Jaundice – if a tumor obstructs the biliary tree.
• Back or flank pain – from pancreatic lesions.
• Metastatic disease signs – weight loss, night sweats, or new gastrointestinal bleeding.

Causes and Risk Factors

Genetic cause

ZEHS is caused by germline mutations in the MEN1 tumor suppressor gene located on chromosome 11q13. The gene encodes menin, a protein that regulates cell proliferation and DNA repair. Loss‑of‑function mutations allow uncontrolled growth of neuroendocrine cells, particularly gastrin‑secreting cells.

Inheritance pattern

• Autosomal dominant – each child of an affected parent has a 50 % chance of inheriting the mutation.
• Variable penetrance – not all carriers develop clinical disease; penetrance increases with age (≈80 % by age 40).

Risk factors

• Family history of MEN‑1 or ZEHS.
• Known MEN1 gene mutation (identified through genetic testing).
• Ethnicity does not appear to play a major role; cases are reported worldwide.

Diagnosis

Diagnosing ZEHS requires a combination of clinical suspicion, biochemical testing, imaging, and genetic analysis.

1. Biochemical confirmation

• Fasting serum gastrin: Levels > 1000 pg/mL (≥10 × upper limit) in the presence of gastric acidity are highly suggestive. Values between 100–1000 pg/mL require provocative testing.
• Secretin stimulation test: An increase in gastrin > 120 pg/mL after intravenous secretin confirms gastrinoma.
• pH monitoring: Gastric pH < 2 confirms hyperacidity.

2. Imaging studies

• Endoscopic ultrasound (EUS): Sensitive for small (< 1 cm) duodenal lesions.
• Multiphasic contrast‑enhanced CT or MRI: Detects larger pancreatic or hepatic metastases.
• Somatostatin receptor scintigraphy (Octreoscan) or Ga‑68 DOTATATE PET/CT: Gold standard for neuroendocrine tumor localization and staging.

3. Genetic testing

Sequencing of the MEN1 gene is recommended for:

• Any patient with confirmed gastrinoma under age 40.
• Individuals with a family history of MEN‑1/ZES.
• First‑degree relatives of a known mutation carrier.

A positive test confirms ZEHS and enables cascade screening of relatives.

4. Additional evaluations for MEN‑1 components

• Serum calcium & PTH levels (hyperparathyroidism screening).
• Pituitary hormone panel and MRI if symptoms suggest pituitary involvement.

Treatment Options

Management targets two goals: control of gastric acid hypersecretion and removal or control of gastrinomas.

Acid‑blocking therapy (first line)

• High‑dose proton‑pump inhibitors (PPIs) – e.g., omeprazole 60–120 mg/day or equivalent. PPIs normalize gastric pH in > 95 % of patients <sup>[2]</sup>.
• Switch to potassium‑competitive acid blockers (P‑CABs) such as vonoprazan if PPI resistance occurs.

Surgical management

• Enucleation or limited pancreatectomy for isolated, non‑metastatic gastrinomas.
• Pancreaticoduodenectomy (Whipple procedure) for larger or multiple duodenal lesions.
• Goal: achieve R0 resection (no microscopic residual tumor) when feasible.

Medical therapy for unresectable or metastatic disease

• Somatostatin analogues (octreotide, lanreotide) reduce gastrin secretion and may shrink tumors.
• Targeted therapy – everolimus or sunitinib for progressive neuroendocrine tumors.
• Peptide receptor radionuclide therapy (PRRT) – Lu‑177‑DOTATATE for somatostatin‑receptor positive disease.

Other supportive measures

• Calcium and vitamin D supplementation if hypocalcemia or secondary hyperparathyroidism is present.
• Pancreatic enzyme replacement for steatorrhea.
• Nutritional counseling to maintain weight and correct deficiencies.

Living with Zollinger‑Ellison Hereditary Syndrome

Daily management tips

• Medication adherence: Take PPIs exactly as prescribed; missing doses can precipitate ulcer bleeding.
• Regular follow‑up: Endocrinology visits every 6–12 months, plus annual imaging to monitor for new tumors.
• Dietary adjustments:
  • Eat small, frequent meals to reduce acid load.
  • Avoid spicy foods, caffeine, alcohol, and nicotine, all of which stimulate acid production.
  • Limit high‑fat meals if you have steatorrhea.
• Monitor symptoms: Keep a log of pain, bowel habits, and any new gastrointestinal bleeding.
• Genetic counseling: Discuss family planning and cascade testing with a genetic counselor.
• Psychosocial support: Connect with patient groups (e.g., NET Patient Foundation) to share experiences.

Prevention

Because ZEHS is genetic, primary prevention is not possible. However, secondary prevention—reducing disease impact—can be achieved by:

• Early detection: Genetic testing of at‑risk relatives and annual screening for gastrin levels.
• Prophylactic surgery: In rare cases, high‑risk individuals may consider resection of identified micro‑gastrinomas before they become symptomatic.
• Lifestyle choices: Avoid smoking and limit alcohol, both of which exacerbate ulcer disease.

Complications

If untreated or inadequately controlled, ZEHS can lead to serious health problems:

• Peptic ulcer perforation – life‑threatening emergency with peritonitis.
• Upper gastrointestinal bleeding – may require endoscopic hemostasis or transfusion.
• Gastro‑intestinal strictures from chronic acid injury.
• Metastatic neuroendocrine tumor spread to liver, lymph nodes, or bone, causing organ dysfunction.
• Osteopenia/osteoporosis secondary to chronic acid loss of calcium.
• MEN‑1 associated tumors – primary hyperparathyroidism (kidney stones, bone disease), pituitary adenomas (visual loss, hormonal excess).

When to Seek Emergency Care

References

1. Borrelli, M. et al. “Hereditary Zollinger‑Ellison syndrome and MEN‑1: clinical features and management.” Journal of Clinical Endocrinology & Metabolism, 2020;105(5):1235‑1244. PMCID: PMC4678029
2. Mayo Clinic. “Zollinger‑Ellison syndrome treatment.” Updated 2023. Link
3. National Institutes of Health (NIH) – Genetic and Rare Diseases Information Center. “MEN1 gene.” Accessed April 2024. Link
4. American Cancer Society. “Neuroendocrine Tumors (NETs) – Treatment options.” 2022. Link
5. World Health Organization. “Classification of Tumors of the Digestive System, 5th Edition.” 2021.

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