TBCB

protein-coding

tubulin folding cofactor B

Gene summary

Predicted to enable microtubule plus-end binding activity. Predicted to be involved in cytoplasmic microtubule organization. Located in cytosol. [provided by Alliance of Genome Resources, Jul 2025]

Previous symbols:

CKAP1

MANE transcript

NM_001281.3

Inheritance

—

ClinVar variants

U:53B:1

Top phenotype

Neurodevelopmental disorder with behavioral abnormalities and childhood-onset spastic paraplegia

gnomAD constraint

pLI —, LoF o/e 0.43

Max pathogenic AF

—

Genomic locus

chr19:36,114,289-36,125,947

External References & Databases

Ensembl (ENSG00000105254)

Transcript & Mutation Effects

hg38 • Region Span ~11.7 kb

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GenCC Phenotypes & Disease Associations

Curated gene-disease validity assertions and inheritance patterns

No GenCC data available for this gene.

ClinVar Associated Diseases & Phenotypes

Reported disease conditions connected to TBCB variants in ClinVar

3 Conditions Cataloged

not specifiedTotal: 49

not providedTotal: 2

Neurodevelopmental disorder with behavioral abnormalities and childhood-onset spastic paraplegiaTotal: 1

ClinVar Variants & Pathogenicity by Type

Statistics based on transcript NM_001281.3. Only rare variants are included.

We include only reliable ClinVar variants with their consequences to MANE Select, MANE Plus Clinical transcripts, or transcripts with TSL equal to 1. Click a count to filter the variants table below.

Slight differences between displayed counts and ClinVar may occur due to a different transcript/consequence chosen by our variant effect predictor, or because we classify Benign/Likely benign as Likely benign and Pathogenic/Likely pathogenic as Likely pathogenic.

Effect	PathogenicP	Likely pathogenicLP	VUS	Likely benignLB	BenignB	Sum
synonymous				1 clinvar		1
missense			53 clinvar			53
nonsense						0
start loss						0
frameshift						0
splice donor/acceptor (+/-2bp)						0
Total	0	0	53	1	0	54

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Transcript Catalog

Annotated transcript isoforms across RefSeq and Ensembl databases

Showing 4 of 32 transcripts

Transcript ID	Source	Protein ID	Coding Exons	MANE Status
NM_001281.3	RefSeq	NP_001272.2	6	MANE Select
ENST00000221855.8	Ensembl	ENSP00000221855.3	6	MANE Select
NM_001300971.3	RefSeq	NP_001287900.1	5	Standard
ENST00000585746.1	Ensembl	ENSP00000467487.1	5	Standard

Gene Ontology (GO) Annotations & Pathways

Biological processes, molecular functions, cellular components and pathways

Pathways ConsensusPathDB

Metabolism of proteins
Protein folding
Post-chaperonin tubulin folding pathway

Biological Process

nervous system development
cell differentiation

Molecular Function

protein binding

Cellular Component

cytoplasm
cytosol
microtubule
microtubule cytoskeleton

gnomAD Constraint

Source: gnomAD

Gene type: protein_coding
Transcript type: protein_coding
Transcript: ENST00000221855
Coding exons: 6
Length: 11659
Individuals with no LoFs: 125738
Homozygous LoFs: 0
Heterozygous LoFs: 10
Defined: 125748
p: 0.0000398

	Z-Score	Observed	Expected	Observed/Expected	Mutation Rate	Total Possible
Missense	0.798	125	153	0.818	0.00000977	1556
Missense (PolyPhen)		20	34.127	0.58604		374
Synonymous	-0.550	72	66.3	1.09	0.00000460	473
Loss of Function	1.81	5	11.7	0.428	5.02e-7	142

Population LoF Frequency

Population	CAF	p-value	Status
African	0.00012	0.00012	rare
Latino/Admixed American	0	0.0	absent
Ashkenazi Jewish	0	0.0	absent
East Asian	0	0.0	absent
Finnish	0.000046	0.000046	rare
European (Non-Finnish)	0.000028	0.000026	rare
South Asian	0.000098	0.000098	rare
Other	0.00017	0.00016	rare

dbNSFP Gene Annotations

Source: dbNSFP

Function: FUNCTION: Binds to alpha-tubulin folding intermediates after their interaction with cytosolic chaperonin in the pathway leading from newly synthesized tubulin to properly folded heterodimer (PubMed:9265649). Involved in regulation of tubulin heterodimer dissociation. May function as a negative regulator of axonal growth (By similarity). {ECO:0000250|UniProtKB:Q9D1E6, ECO:0000269|PubMed:9265649}.;

Recessive Scores

pRec: 0.105

Intolerance Scores

LoFtool: 0.290
RVIS EVS: -0.38
RVIS percentile EVS: 27.42

Essentials

Essential (CRISPR): E
Essential (CRISPR2): S
Essential (gene trap): E
Indispensability pred.: E
Indispensability score: 0.634

Gene Damage Prediction

	All	Recessive	Dominant
Mendelian	Medium	Medium	Medium
Primary Immunodeficiency	Medium	Medium	Medium
Cancer	Medium	Medium	Medium