SERPINA7
Serpin Family A Member 7 (Thyroxine-Binding Globulin)
Gene Information Card
| Symbol | SERPINA7 |
|---|---|
| Full Name | Serpin Family A Member 7 |
| Gene Type | Protein coding |
| Chromosomal Location | Xq22.3 |
| NCBI Gene ID | 7157 ncbi.nlm.nih.gov/gene/7157 |
| Ensembl ID | ENSG00000170099 |
| UniProt ID | P05543 |
| OMIM ID | 314200 |
| HGNC ID | 1540 |
| Aliases | TBG, TBG1, T4-binding globulin, thyroxine-binding globulin |
Description
SERPINA7 encodes thyroxine-binding globulin (TBG), a serine protease inhibitor (serpin) family member that is the major thyroid hormone transport protein in blood. TBG binds approximately 75% of circulating thyroxine (T4) and triiodothyronine (T3), regulating their bioavailability and metabolic clearance. The gene is located on the X chromosome, and mutations can lead to TBG deficiency or excess, affecting thyroid function tests.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Thyroxine-Binding Globulin Deficiency | Loss-of-function mutations in SERPINA7 reduce TBG levels, decreasing total T4/T3 binding capacity without altering free hormone levels; typically euthyroid but may show abnormal thyroid function tests. | ClinVar, OMIM #314200 |
| Thyroxine-Binding Globulin Excess | Gain-of-function or duplication of SERPINA7 increases TBG levels, elevating total T4/T3 but free hormones remain normal; euthyroid state. | OMIM #314200 |
| Familial Euthyroid Hyperthyroxinemia | Elevated total T4 due to TBG excess, mimicking hyperthyroidism but with normal free T4 and TSH. | ClinVar, OMIM #314200 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.5 | High |
| Kidney | 0.8 | Low |
| Lung | 0.3 | Not detected |
| Heart | 0.1 | Not detected |
| Brain | 0.0 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 15.2 | Hepatocellular carcinoma cell line; high TBG expression |
| Huh-7 | 11.8 | Hepatoma cell line |
| HEK293 | 0.5 | Low expression; not primary site |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.909G>A (p.Trp303*) | Nonsense | Rare | Loss of function; TBG deficiency |
| c.631C>T (p.Arg211Cys) | Missense | Rare | Reduced TBG stability and secretion |
| c.1007T>C (p.Leu336Pro) | Missense | Rare | Impaired thyroxine binding |
| c.1198G>A (p.Gly400Arg) | Missense | Rare | Complete TBG deficiency |
Mutation functional classification
Loss of Function (LOF)
Most SERPINA7 mutations cause partial or complete loss of TBG function, leading to reduced thyroxine-binding capacity and low total T4/T3 levels.
Gain of Function (GOF)
Duplications or promoter variants increasing TBG expression result in elevated total T4/T3 without hyperthyroidism.
Dominant Negative (DN)
Not reported for SERPINA7; X-linked inheritance typically results in hemizygous expression in males.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Thyroid hormone synthesis and transport (Reactome: R-HSA-209968)
• Serine protease inhibitors (Serpins) (Reactome: R-HSA-168249)
• Protein metabolism (UniProt: P05543)
Protein Summary
Thyroxine-binding globulin (TBG) is a 54 kDa glycoprotein synthesized primarily in the liver. It belongs to the serpin superfamily but lacks protease inhibitory activity due to a reactive center loop mutation. TBG binds thyroid hormones with high affinity (Kd ~10^-10 M for T4), serving as the main carrier in plasma. Its half-life is modulated by sialylation and proteolytic cleavage. TBG levels are influenced by estrogen, pregnancy, and liver disease. Mutations in SERPINA7 cause inherited TBG abnormalities, which are clinically benign but can confound thyroid function test interpretation.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SERPINA7 Knockout HEK293 Cell Line | EDJ-KQ3263 | Human | 6906 | Details Get a Quote |
| SERPINA7 Knockout HeLa Cell Line | EDJ-KQ54616 | Human | 6906 | Details Get a Quote |
| SERPINA7 Knockout A-549 Cell Line | EDJ-KQ63097 | Human | 6906 | Details Get a Quote |
| SERPINA7 Knockout HCT 116 Cell Line | EDJ-KQ71570 | Human | 6906 | Details Get a Quote |
Displaying Records 1 To 4 Of 4 Records
