19-6495966-G-C

Variant names:

• chr19-6495966-G-C
• rs587777468
• NM_006087.4:c.533C>G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Moderate PP5_Moderate

The NM_006087.4(TUBB4A):​c.533C>G​(p.Thr178Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TUBB4A NM_006087.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2 O:1
• Conservation: PhyloP100: 9.80

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.914
• PP5: Variant 19-6495966-G-C is Pathogenic according to our data. Variant chr19-6495966-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 139453.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBB4A	NM_006087.4	c.533C>G	p.Thr178Arg	missense_variant	Exon 4 of 4	ENST00000264071.7	NP_006078.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TUBB4A	ENST00000264071.7	c.533C>G	p.Thr178Arg	missense_variant	Exon 4 of 4	1	NM_006087.4	ENSP00000264071.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypomyelinating leukodystrophy 6 Pathogenic:2 Other:1

May 21, 2014

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

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GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Dec 29, 2020

Molecular Diagnostics Lab, Nemours Children's Health, Delaware

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant (c.533C>G, p.Thr178Arg) has not been observed in population databases (gnomAD). It has been reported in the literature (PMID 24850488, PMID 30476126). Variant prediction programs suggest a deleterious effect, although no functional studies have been published. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.10
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Benign	0.26	T;.;.;T
Eigen	Pathogenic	0.93
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.97	D;D;D;D
M_CAP	Pathogenic	0.82	D
MetaRNN	Pathogenic	0.91	D;D;D;D
MetaSVM	Uncertain	0.52	D
MutationAssessor	Pathogenic	3.7	H;.;.;.
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-4.9	D;.;.;.
REVEL	Pathogenic	0.89
Sift4G	Uncertain	0.017	D;D;.;.
Polyphen		1.0	D;.;.;.
Vest4		0.94
MutPred		0.63		Loss of phosphorylation at T178 (P = 0.0853);.;.;.;
MVP		0.84
MPC		2.9
ClinPred		1.0	D
GERP RS		4.0
Varity_R		0.96
gMVP		0.98

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

Other links and lift over

dbSNP: rs587777468; hg19: chr19-6495977;