BTD Gene (Biotinidase)
Biotinidase deficiency, biotin metabolism, and genetic testing
Gene Information Card
| Symbol | BTD |
|---|---|
| Full Name | Biotinidase |
| Gene Type | protein-coding |
| Chromosomal Location | 3p25.1 |
| NCBI Gene ID | 686 ncbi.nlm.nih.gov/gene/686 |
| Ensembl ID | ENSG00000169814 |
| UniProt ID | P43251 |
| OMIM ID | 609019 |
| HGNC ID | 1122 |
| Aliases | biotinidase, biotin deficiency, BTD deficiency |
Description
The BTD gene encodes biotinidase, an enzyme that recycles biotin (vitamin B7) from biocytin and dietary protein-bound biotin. Biotinidase deficiency (OMIM #253260) is an autosomal recessive disorder leading to multiple carboxylase deficiency, metabolic acidosis, and neurological symptoms if untreated.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Biotinidase deficiency | Loss-of-function mutations in BTD impair biotin recycling, causing multiple carboxylase deficiency and metabolic acidosis. | ClinVar, OMIM #253260 |
| Multiple carboxylase deficiency (biotin-responsive) | Deficient biotinidase activity reduces biotin availability for carboxylases, leading to organic acidemia. | OMIM, NCBI GeneReviews |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Liver | 12.3 | Medium |
| Kidney | 8.7 | Medium |
| Brain | 5.1 | Low |
| Heart | 4.2 | Low |
| Lung | 3.8 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HepG2 | 10.5 | Hepatocyte cell line |
| HEK293 | 7.2 | Embryonic kidney cells |
| SH-SY5Y | 4.1 | Neuroblastoma cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1330G>C (p.Asp444His) | Missense | Common in symptomatic deficiency | Reduced enzyme activity |
| c.511G>A (p.Ala171Thr) | Missense | Common in partial deficiency | Mild reduction in activity |
| c.1489C>T (p.Arg497*) | Nonsense | Rare | Complete loss of function |
Mutation functional classification
Loss of Function (LOF)
Most BTD mutations cause loss of biotinidase activity, leading to biotinidase deficiency.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
Not described; disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • biotinidase activity (GO:0004060) | • biotin metabolic process (GO:0006768) |
| • cytoplasm (GO:0005737) | • extracellular region (GO:0005576) |
Pathways
• Biotin metabolism (Reactome: R-HSA-196849)
• Metabolism of water-soluble vitamins and cofactors
Protein Summary
Biotinidase (EC 3.5.1.12) is a 543-amino acid glycoprotein that cleaves biocytin to release biotin. It is secreted into serum and also localized in lysosomes. Deficiency leads to biotin-responsive multiple carboxylase deficiency.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| BTD Knockout HEK293 Cell Line | EDJ-KQ4150 | Human | 686 | Details Get a Quote |
| UBTD1 Knockout HEK293 Cell Line | EDJ-KQ9427 | Human | 80019 | Details Get a Quote |
| UBTD2 Knockout HEK293 Cell Line | EDJ-KQ10848 | Human | 92181 | Details Get a Quote |
| MBTD1 Knockout HEK293 Cell Line | EDJ-KQ12117 | Human | 54799 | Details Get a Quote |
| UBTD1 Knockout A-549 Cell Line | EDJ-KQ36087 | Human | 80019 | Details Get a Quote |
| UBTD1 Knockout HCT 116 Cell Line | EDJ-KQ36088 | Human | 80019 | Details Get a Quote |
| UBTD1 Knockout HeLa Cell Line | EDJ-KQ36089 | Human | 80019 | Details Get a Quote |
| BTD Knockout A-549 Cell Line | EDJ-KQ26586 | Human | 686 | Details Get a Quote |
| BTD Knockout HCT 116 Cell Line | EDJ-KQ26587 | Human | 686 | Details Get a Quote |
| BTD Knockout HeLa Cell Line | EDJ-KQ26588 | Human | 686 | Details Get a Quote |
| UBTD2 Knockout A-549 Cell Line | EDJ-KQ37224 | Human | 92181 | Details Get a Quote |
| UBTD2 Knockout HCT 116 Cell Line | EDJ-KQ38512 | Human | 92181 | Details Get a Quote |
| UBTD2 Knockout HeLa Cell Line | EDJ-KQ38513 | Human | 92181 | Details Get a Quote |
| MBTD1 Knockout A-549 Cell Line | EDJ-KQ39545 | Human | 54799 | Details Get a Quote |
| MBTD1 Knockout HCT 116 Cell Line | EDJ-KQ40801 | Human | 54799 | Details Get a Quote |
Displaying Records 1 To 15 Of 16 Records
