NM_006087.4:c.1331C>T

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BS1_SupportingBS2

The NM_006087.4(TUBB4A):c.1331C>T(p.Ala444Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000613 in 1,613,754 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000063 ( 0 hom. )

Consequence

TUBB4A
NM_006087.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 9.55

Variant links:

Genes affected

TUBB4A (HGNC:20774): (tubulin beta 4A class IVa) This gene encodes a member of the beta tubulin family. Beta tubulins are one of two core protein families (alpha and beta tubulins) that heterodimerize and assemble to form microtubules. Mutations in this gene cause hypomyelinating leukodystrophy-6 and autosomal dominant torsion dystonia-4. Alternate splicing results in multiple transcript variants encoding different isoforms. A pseudogene of this gene is found on chromosome X. [provided by RefSeq, Jan 2014]

TUBB4A links:

ENSG00000268191 (HGNC:):

ENSG00000268191 links:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

PP2

Missense variant in the TUBB4A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 39 curated pathogenic missense variants (we use a threshold of 10). The gene has 34 curated benign missense variants. Gene score misZ: 4.2623 (above the threshold of 3.09). Trascript score misZ: 5.1229 (above the threshold of 3.09). GenCC associations: The gene is linked to torsion dystonia 4, TUBB4A-related neurologic disorder, hypomyelinating leukodystrophy 6.

BS1

Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.000046 (7/152178) while in subpopulation NFE AF= 0.0000882 (6/67992). AF 95% confidence interval is 0.0000376. There are 0 homozygotes in gnomad4. There are 4 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

BS2

High AC in GnomAd4 at 7 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBB4A	NM_006087.4 link	c.1331C>T	p.Ala444Val	missense_variant	Exon 4 of 4	ENST00000264071.7	NP_006078.2	P04350

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TUBB4A	ENST00000264071.7 link	c.1331C>T	p.Ala444Val	missense_variant	Exon 4 of 4	1	NM_006087.4	ENSP00000264071.1		P04350
ENSG00000268191	ENST00000596027.1 link	n.*143G>A		downstream_gene_variant		5

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152060

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000882

Gnomad OTH

AF:

0.000479

GnomAD3 exomes

AF:

0.0000518

AC:

AN:

251040

Hom.:

AF XY:

0.0000516

AC XY:

AN XY:

135684

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000106

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000629

AC:

AN:

1461576

Hom.:

Cov.:

AF XY:

0.0000564

AC XY:

AN XY:

727092

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000773

Gnomad4 OTH exome

AF:

0.0000663

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152178

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74408

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000882

Gnomad4 OTH

AF:

0.000474

Alfa

AF:

0.0000329

Hom.:

Bravo

AF:

0.0000227

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000659

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000178

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Hypomyelinating leukodystrophy 6

Uncertain:1

Aug 15, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C0"). This missense change has been observed in at least one individual who was not affected with TUBB4A-related conditions (Invitae). This variant has not been reported in the literature in individuals affected with TUBB4A-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 444 of the TUBB4A protein (p.Ala444Val). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Uncertain

0.063

BayesDel_noAF

Benign

-0.15

CADD

Benign

DANN

Benign

0.97

DEOGEN2

Benign

0.029

Eigen

Benign

0.067

Eigen_PC

Benign

0.12

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.96

M_CAP

Uncertain

0.23

MetaRNN

Uncertain

0.43

MetaSVM

Benign

-0.52

MutationAssessor

Benign

0.0

PrimateAI

Uncertain

0.64

PROVEAN

Benign

-0.36

REVEL

Uncertain

0.39

Sift4G

Uncertain

0.0040

Polyphen

0.81

Vest4

0.60

MVP

0.92

MPC

1.4

ClinPred

0.24

GERP RS

3.3

Varity_R

0.18

gMVP

0.95

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over