rs797045074

Variant names:

• chr19-6495335-C-G
• rs797045074
• NM_006087.4:c.1164G>C

Your query was ambiguous. Multiple possible variants found:

• chr19-6495335-C-G
• chr19-6495335-C-T

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_006087.4(TUBB4A):​c.1164G>C​(p.Met388Ile) 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: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 7.77

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 Pathogenic. Variant got 15 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, 0.949
• PP5: Variant 19-6495335-C-G is Pathogenic according to our data. Variant chr19-6495335-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 209201.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBB4A	NM_006087.4	c.1164G>C	p.Met388Ile	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.1164G>C	p.Met388Ile	missense_variant	Exon 4 of 4	1	NM_006087.4	ENSP00000264071.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypomyelinating leukodystrophy 6 Pathogenic:2

Jun 20, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt TUBB4A protein function. ClinVar contains an entry for this variant (Variation ID: 209201). This missense change has been observed in individual(s) with hypomyelinating leukodystrophy (PMID: 24785942, 32581362, 33597727). In at least one individual the variant was observed to be de novo. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces methionine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 388 of the TUBB4A protein (p.Met388Ile). -

Nov 05, 2014

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Likely pathogenicity based on finding it once in our laboratory de novo in a 22-year-old female with spastic paraplegia, epilepsy, hyperreflexia, absent speech, severe cognitive delays, severe scoliosis, leukodystrophy, ventriculomegaly, microcephaly, osteoporosis, hip dislocation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Benign	0.099	T
Eigen	Pathogenic	0.79
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.90	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	3.7	H
PrimateAI	Pathogenic	0.87	D
PROVEAN	Benign	-2.1	N
REVEL	Pathogenic	0.99
Sift4G	Uncertain	0.010	D
Polyphen		1.0	D
Vest4		0.85
MutPred		0.80		Loss of MoRF binding (P = 0.0887);
MVP		0.91
MPC		1.6
ClinPred		0.99	D
GERP RS		3.4
Varity_R		0.92
gMVP		0.99

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: rs797045074; hg19: chr19-6495346;