Other enteropathies

Lesion

Poor sanitation, faulty immune control, missing enzymes and broken cell machinery can all stop the small bowel absorbing food.

Updated Nov 12, 2026

Key points

Environmental enteric dysfunction: chronic exposure to faecal contamination; malabsorption, malnutrition, stunting and poor response to oral vaccines; affects well over a hundred million children; antibiotics and supplements do not reverse it.
Autoimmune enteropathy: severe diarrhoea in young children; the X-linked IPEX form is caused by FOXP3 loss (no regulatory T cells); antibodies to enterocytes and goblet cells.
Lactase deficiency: osmotic diarrhoea, bloating and gas after milk; normal histology; acquired loss with age is very common, the congenital autosomal recessive form is rare; temporary loss after enteric infections.
Microvillus inclusion disease: MYO5B mutations; intractable diarrhoea from the first days of life; apical vesicles containing microvilli seen by electron microscopy or CD10 and villin stains.
Abetalipoproteinaemia: MTP mutation; no apoB lipoproteins; vacuolated, lipid-laden enterocytes; acanthocytes; fat-soluble vitamin deficiency.

What it is

Several less common disorders cause malabsorption by different routes. Environmental enteric dysfunction affects children in places with poor sanitation; autoimmune enteropathy reflects failed immune regulation; lactase deficiency is a missing brush-border enzyme; microvillus inclusion disease is a defect of membrane trafficking; abetalipoproteinaemia is a failure to package fat. Each has a distinctive clue, often in the biopsy or blood smear.

Five rarer causes of malabsorption

Disorder	Defect	Biopsy clue	Other clue
Environmental enteric dysfunction	Barrier and immune damage from repeated faecal exposure	Inflammatory infiltrate, milder villous blunting than coeliac	Stunting in poor-sanitation settings
Autoimmune enteropathy	Failed regulatory T cells (FOXP3 in IPEX)	Neutrophils and crypt apoptosis; fewer intraepithelial lymphocytes than coeliac	Endocrinopathy, autoantibodies
Lactase deficiency	Missing brush-border lactase	Normal	Symptoms after dairy; hydrogen breath test
Microvillus inclusion disease	MYO5B: membrane trafficking	Microvillus inclusions (electron microscopy, CD10)	Diarrhoea from birth
Abetalipoproteinaemia	MTP: cannot load lipid onto apoB	Lipid vacuoles in enterocytes (oil red O)	Acanthocytes, absent apoB lipoproteins

Clinical notes

Environmental enteric dysfunction is relevant in rural and poor urban areas of Latin America and contributes to childhood stunting.
Total parenteral nutrition and small-bowel transplantation are the only options for microvillus inclusion disease.

Test yourself

Think of the answer, then tap the question to see it.

Which gene is mutated in the IPEX form of autoimmune enteropathy?

FOXP3, the transcription factor of regulatory T cells.

Why is the biopsy normal in lactase deficiency?

The defect is biochemical (a missing brush-border enzyme), not structural.

What blood-smear finding accompanies abetalipoproteinaemia?

Acanthocytes, red cells with spiky projections from membrane lipid abnormalities.

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Connections

← All of general pathology

Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: Lactose intolerance: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2025); Abetalipoproteinemia: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2025); Microvillus inclusion disease: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2025).

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