TUBB4A

Chr 19AD

tubulin beta 4A class IVa

Also known as: DYT4, TUBB4, beta-5

This gene encodes a beta tubulin protein that heterodimerizes with alpha tubulin to form microtubules, which are essential components of the cellular cytoskeleton. Mutations cause autosomal dominant dystonia-4 (torsion dystonia) and hypomyelinating leukodystrophy-6 through a dominant-negative mechanism where mutant proteins disrupt normal microtubule function. Both conditions follow autosomal dominant inheritance with the dystonia typically presenting with focal onset and the leukodystrophy causing developmental delays and motor dysfunction.

GeneReviewsOMIMResearchSummary from RefSeq, OMIM, UniProt, Mechanism
GOFmechanismADLOEUF 0.672 OMIM phenotypes
VCEP Guidelines: LeukodystrophyPilot
ClinGen Panel
Clinical SummaryTUBB4A
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Gene-Disease Validity (ClinGen)
TUBB4A-related neurologic disorder · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.29) despite low pLI — interpret in context.
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Clinical Trials
1 active or recruiting trial — potential therapeutic options may be available
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GeneReview available — TUBB4A
Authoritative clinical overview · Recommended first read
Open GeneReview ↗

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Missense constrained — critical functional residues
LoF Constraint
0.67LOEUF
pLI 0.109
Z-score 2.41
OE 0.29 (0.140.67)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
4.26Z-score
OE missense 0.31 (0.260.37)
93 obs / 301.1 exp
Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios
LoF OE0.29 (0.140.67)
00.351.4
Missense OE0.31 (0.260.37)
00.61.4
Synonymous OE1.16
01.21.6
LoF obs/exp: 4 / 13.6Missense obs/exp: 93 / 301.1Syn Z: -1.48
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveTUBB4A-related hypomyelination with atrophy of the basal ganglia and cerebellumGOFAD
DN
0.74top 25%
GOF
0.5465th %ile
LOF
0.3646th %ile

The highest-scoring mechanism for this gene is dominant-negative.

DNprediction above median · 1 literature citation

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Literature Evidence

DNTUBB4A is highly expressed in neurons, and Simons et al. (2013) suggested that the mutation may result in a dominant-negative effect on tubulin dimerization, microtubule polymerization, or microtubule stability in neurons with a secondary involvement of glial cells.PMID:23582646

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

TUBB4A · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold
Clinical Literature
Open Research Assistant →
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC