Brush border
enzyme deficiences
Noor fatima & roshaan CHEEMA
,Introduction
What Are Brush Border Enzymes?
The small intestine has microscopic finger-like projections
called villi, and on them are even smaller microvilli, forming
the brush border.
These microvilli produce digestive enzymes that help break
down carbohydrates into absorbable units.
Important brush border enzymes include:
Lactase → breaks lactose → glucose + galactose
Sucrase →breaks sucrose →glucose + fructose
Maltase → breaks maltose →glucose + glucose
When these enzymes are deficient, undigested sugars are left
in the intestine→osmotic diarrhea + gas + bloating
, Types of Enzyme Deficiencies
Type of Deficiency Cause Example
Congenital Genetic Absence Congenital Lactase/
(from birth) Isomaltase/Sucrase deficiency
Primary Lactase Non-Persistence Most cases of
(genetic decline after childhood) (Natural decline with age) lactose intolerance
Secondary Damage to intestinal mucosa Lactose intolerance after IBS,
(acquired due to disease) Gastroenteritis,Celiac disease
& Crohn’s disease
enzyme deficiences
Noor fatima & roshaan CHEEMA
,Introduction
What Are Brush Border Enzymes?
The small intestine has microscopic finger-like projections
called villi, and on them are even smaller microvilli, forming
the brush border.
These microvilli produce digestive enzymes that help break
down carbohydrates into absorbable units.
Important brush border enzymes include:
Lactase → breaks lactose → glucose + galactose
Sucrase →breaks sucrose →glucose + fructose
Maltase → breaks maltose →glucose + glucose
When these enzymes are deficient, undigested sugars are left
in the intestine→osmotic diarrhea + gas + bloating
, Types of Enzyme Deficiencies
Type of Deficiency Cause Example
Congenital Genetic Absence Congenital Lactase/
(from birth) Isomaltase/Sucrase deficiency
Primary Lactase Non-Persistence Most cases of
(genetic decline after childhood) (Natural decline with age) lactose intolerance
Secondary Damage to intestinal mucosa Lactose intolerance after IBS,
(acquired due to disease) Gastroenteritis,Celiac disease
& Crohn’s disease
