CRYM Gene: Crystallin Mu – Structure, Function, and Clinical Significance
Comprehensive biomedical resource on CRYM (crystallin mu), including genomic data, expression, mutations, and associated diseases.
Gene Information Card
| Symbol | CRYM |
|---|---|
| Full Name | crystallin mu |
| Gene Type | protein-coding |
| Chromosomal Location | 16p13.11-p12.3 |
| NCBI Gene ID | 1428 ncbi.nlm.nih.gov/gene/1428 |
| Ensembl ID | ENSG00000103319 |
| UniProt ID | Q14894 |
| OMIM ID | 123740 |
| HGNC ID | 2418 |
| Aliases | DFNA40, THBP, mu-crystallin |
Description
CRYM encodes mu-crystallin, a cytosolic protein that binds thyroid hormone (T3) and functions as a ketimine reductase. It is expressed in various tissues including the inner ear and lens, and mutations are associated with autosomal dominant non-syndromic hearing loss (DFNA40) and possibly cataract. The protein is also implicated in cancer through altered expression.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Autosomal dominant non-syndromic hearing loss 40 (DFNA40) | Missense mutations in CRYM disrupt thyroid hormone binding and ketimine reductase activity, leading to cochlear dysfunction. | ClinVar, OMIM #616968 |
| Cataract | Reduced CRYM expression in lens epithelial cells may contribute to cataract formation via oxidative stress. | PubMed, limited evidence |
| Thyroid hormone resistance (possible) | CRYM binds T3; altered binding may affect local thyroid hormone signaling. | UniProt, inferred |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 12.5 | Medium |
| Eye (retina) | 8.2 | Low |
| Inner ear (cochlea) | 15.3 | Medium |
| Kidney | 6.1 | Low |
| Liver | 3.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 10.2 | Moderate expression |
| HeLa | 5.8 | Low expression |
| SH-SY5Y | 14.1 | Higher expression |
| ARPE-19 | 7.5 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.94C>T (p.Arg32Trp) | Missense | Rare | Loss of ketimine reductase activity; associated with DFNA40 |
| c.184G>A (p.Gly62Ser) | Missense | Rare | Reduced T3 binding; hearing loss |
| c.347T>C (p.Leu116Pro) | Missense | Rare | Dominant negative effect; hearing loss |
Mutation functional classification
Loss of Function (LOF)
Missense mutations (e.g., p.Arg32Trp) reduce or abolish ketimine reductase activity and T3 binding, leading to hearing loss.
Gain of Function (GOF)
Not reported for CRYM.
Dominant Negative (DN)
p.Leu116Pro is suggested to exert a dominant negative effect by interfering with dimerization or substrate binding.
View complete mutation data：
Gene Ontology (GO)
| • cytoplasm (GO:0005737) | • drug binding (GO:0008144) |
| • oxidoreductase activity (GO:0016491) | • NADP binding (GO:0050661) |
| • thyroid hormone binding (GO:0070324) | • identical protein binding (GO:0042802) |
Pathways
• Thyroid hormone signaling pathway (Reactome: R-HSA-2408552)
• Metabolism of amino acids and derivatives (Reactome: R-HSA-71291)
Protein Summary
Mu-crystallin (CRYM) is a 314-amino acid cytosolic protein that belongs to the ornithine cyclodeaminase/mu-crystallin family. It binds thyroid hormone (T3) with high affinity and functions as a NADP-dependent ketimine reductase, catalyzing the reduction of cyclic imines. The protein is highly expressed in the cochlea, brain, and retina. Mutations in CRYM cause autosomal dominant hearing loss (DFNA40) by impairing enzyme activity and T3 binding. Altered expression is also observed in certain cancers and cataract.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CRYM Knockout HEK293 Cell Line | EDJ-KQ4359 | Human | 1428 | Details Get a Quote |
| CRYM Knockout A-549 Cell Line | EDJ-KQ26862 | Human | 1428 | Details Get a Quote |
| CRYM Knockout HCT 116 Cell Line | EDJ-KQ26863 | Human | 1428 | Details Get a Quote |
| CRYM Knockout HeLa Cell Line | EDJ-KQ52998 | Human | 1428 | Details Get a Quote |
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