GALM: Galactose Mutarotase Gene
Essential enzyme in galactose metabolism and associated disorders
Gene Information Card
| Symbol | GALM |
|---|---|
| Full Name | galactose mutarotase (aldose 1-epimerase) |
| Gene Type | protein-coding |
| Chromosomal Location | 2p22.1 |
| NCBI Gene ID | 130589 ncbi.nlm.nih.gov/gene/130589 |
| Ensembl ID | ENSG00000125657 |
| UniProt ID | Q96C23 |
| OMIM ID | 137030 |
| HGNC ID | 24063 |
| Aliases | GLAT, GALM1, MUTAROTASE |
Description
The GALM gene encodes galactose mutarotase (aldose 1-epimerase), an enzyme that catalyzes the interconversion of alpha- and beta-D-galactose, a critical step in the Leloir pathway of galactose metabolism. Mutations in GALM cause galactosemia type IV (OMIM 618881), a rare autosomal recessive disorder characterized by elevated galactose and galactitol levels, cataracts, and hepatomegaly.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Galactosemia type IV | Loss-of-function mutations in GALM impair conversion of beta-D-galactose to alpha-D-galactose, disrupting galactose metabolism and leading to toxic accumulation of galactose and galactitol. | ClinVar, OMIM 618881 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.5 | Medium |
| Kidney | 8.3 | Medium |
| Small intestine | 6.7 | Low |
| Pancreas | 5.1 | Low |
| Brain | 3.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 15.2 | Hepatocellular carcinoma cell line |
| HEK293 | 10.8 | Embryonic kidney cells |
| HeLa | 7.4 | Cervical adenocarcinoma cells |
| K562 | 4.1 | Leukemia cell line |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.580C>T (p.Arg194Ter) | Nonsense | Rare | Loss of function; premature stop codon leading to truncated protein |
| c.1A>G (p.Met1Val) | Missense | Rare | Loss of function; disrupts translation initiation |
| c.626G>A (p.Arg209Gln) | Missense | Rare | Loss of function; reduced enzyme activity |
Mutation functional classification
Loss of Function (LOF)
Pathogenic variants in GALM result in complete or partial loss of galactose mutarotase activity, causing galactosemia type IV.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported.
View complete mutation data：
Gene Ontology (GO)
| • aldose 1-epimerase activity (GO:0004034) | • galactose metabolic process (GO:0006012) |
| • cytosol (GO:0005829) | • cytoplasm (GO:0005737) |
Pathways
• Leloir pathway of galactose metabolism (Reactome R-HSA-70371)
Protein Summary
Galactose mutarotase (UniProt Q96C23) is a 342-amino acid cytoplasmic enzyme that catalyzes the reversible conversion between alpha- and beta-D-galactose. It is essential for the Leloir pathway, enabling further metabolism by galactokinase (GALK1). The protein is expressed in liver, kidney, and other tissues. Loss of function leads to galactosemia type IV.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| GALM Knockout HEK293 Cell Line | EDJ-KQ3511 | Human | 130589 | Details Get a Quote |
| GALM Knockout HCT 116 Cell Line | EDJ-KQ23951 | Human | 130589 | Details Get a Quote |
| GALM Knockout A-549 Cell Line | EDJ-KQ25326 | Human | 130589 | Details Get a Quote |
| GALM Knockout HeLa Cell Line | EDJ-KQ25328 | Human | 130589 | Details Get a Quote |
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