MGAM Gene (Maltase-Glucoamylase)
A key intestinal disaccharidase involved in starch digestion and linked to congenital sucrase-isomaltase deficiency and other gastrointestinal disorders.
Gene Information Card
| Symbol | MGAM |
|---|---|
| Full Name | Maltase-Glucoamylase |
| Gene Type | Protein coding |
| Chromosomal Location | 7q34 |
| NCBI Gene ID | 8972 ncbi.nlm.nih.gov/gene/8972 |
| Ensembl ID | ENSG00000106384 |
| UniProt ID | O43451 |
| OMIM ID | 154360 |
| HGNC ID | 7044 |
| Aliases | MGA, MGAM1, maltase-glucoamylase (alpha-glucosidase) |
Description
The MGAM gene encodes maltase-glucoamylase, an integral membrane protein of the small intestinal brush border. This enzyme catalyzes the final steps of starch digestion, hydrolyzing linear alpha-1,4-linked glucose oligosaccharides to glucose. It is a member of the glycosyl hydrolase family 31 and is essential for carbohydrate absorption. Defects in MGAM are associated with congenital sucrase-isomaltase deficiency (CSID) and may contribute to other digestive disorders.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Congenital sucrase-isomaltase deficiency (CSID) | Loss-of-function mutations in MGAM reduce or abolish maltase-glucoamylase activity, impairing digestion of starch and sucrose. | ClinVar, OMIM |
| Disaccharidase deficiency (general) | Reduced MGAM expression or activity contributes to carbohydrate malabsorption. | NCBI Gene, OMIM |
| Colorectal cancer | Altered MGAM expression has been observed in colorectal tumors, though the mechanism is not fully established. | COSMIC, NCBI Gene |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Small intestine | 78.5 | High |
| Duodenum | 65.2 | High |
| Jejunum | 82.1 | High |
| Ileum | 60.3 | High |
| Colon | 12.4 | Low |
| Kidney | 5.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Caco-2 (colorectal adenocarcinoma) | 45.3 | Enterocyte-like differentiation, high MGAM expression |
| HT-29 (colorectal adenocarcinoma) | 22.7 | Moderate expression |
| HCT 116 (colorectal carcinoma) | 8.9 | Low expression |
| HEK 293 (embryonic kidney) | 1.2 | Very low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.2005C>T (p.Arg669Ter) | Nonsense | Rare | Loss of function, associated with CSID |
| c.2731G>A (p.Gly911Arg) | Missense | Rare | Reduced enzyme activity, CSID |
| c.3536T>C (p.Leu1179Pro) | Missense | Rare | Impaired protein folding and trafficking |
| c.4243C>T (p.Arg1415Cys) | Missense | Rare | Decreased catalytic activity |
Mutation functional classification
Loss of Function (LOF)
Nonsense and missense mutations that reduce or eliminate maltase-glucoamylase activity, leading to carbohydrate malabsorption.
Gain of Function (GOF)
No gain-of-function mutations have been reported for MGAM.
Dominant Negative (DN)
No dominant-negative mutations have been described for MGAM.
View complete mutation data：
Gene Ontology (GO)
| • alpha-glucosidase activity (GO:0090599) | • carbohydrate binding (GO:0030246) |
| • maltose alpha-glucosidase activity (GO:0032450) | • membrane (GO:0016020) |
| • integral component of membrane (GO:0016021) | • carbohydrate metabolic process (GO:0005975) |
| • starch catabolic process (GO:0005983) |
Pathways
• Starch and sucrose metabolism (KEGG: hsa00500)
• Digestion and absorption of carbohydrates (Reactome: R-HSA-189085)
Protein Summary
Maltase-glucoamylase (UniProt O43451) is a 1857-amino acid type II transmembrane glycoprotein localized to the brush border membrane of enterocytes. It consists of two catalytic domains: N-terminal (maltase) and C-terminal (glucoamylase), both belonging to glycosyl hydrolase family 31. The enzyme hydrolyzes alpha-1,4 glycosidic bonds in maltose, maltotriose, and larger oligosaccharides, releasing glucose. It is essential for the final steps of starch digestion and is often co-expressed with sucrase-isomaltase.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| MGAM Knockout HEK293 Cell Line | EDJ-KQ6420 | Human | 8972 | Details Get a Quote |
| MGAM2 Knockout HEK293 Cell Line | EDJ-KQ11233 | Human | 93432 | Details Get a Quote |
| MGAM Knockout A-549 Cell Line | EDJ-KQ29139 | Human | 8972 | Details Get a Quote |
| MGAM Knockout HeLa Cell Line | EDJ-KQ55047 | Human | 8972 | Details Get a Quote |
| MGAM2 Knockout HeLa Cell Line | EDJ-KQ57864 | Human | 93432 | Details Get a Quote |
| MGAM2 Knockout A-549 Cell Line | EDJ-KQ66360 | Human | 93432 | Details Get a Quote |
| MGAM Knockout HCT 116 Cell Line | EDJ-KQ71998 | Human | 8972 | Details Get a Quote |
| MGAM2 Knockout HCT 116 Cell Line | EDJ-KQ74783 | Human | 93432 | Details Get a Quote |
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