rs886043627

Variant names:

• chr12-49185575-C-A
• NM_006009.4:c.791G>T

Your query was ambiguous. Multiple possible variants found:

• chr12-49185575-C-A
• chr12-49185575-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PM5 PP2 PP3_Strong

The NM_006009.4(TUBA1A):​c.791G>T​(p.Arg264Leu) variant causes a missense change. 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R264C) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: TUBA1A NM_006009.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.53

Genes affected

TUBA1A (HGNC:20766): (tubulin alpha 1a) Microtubules of the eukaryotic cytoskeleton perform essential and diverse functions and are composed of a heterodimer of alpha and beta tubulins. The genes encoding these microtubule constituents belong to the tubulin superfamily, which is composed of six distinct families. Genes from the alpha, beta and gamma tubulin families are found in all eukaryotes. The alpha and beta tubulins represent the major components of microtubules, while gamma tubulin plays a critical role in the nucleation of microtubule assembly. There are multiple alpha and beta tubulin genes, which are highly conserved among species. This gene encodes alpha tubulin and is highly similar to the mouse and rat Tuba1 genes. Northern blot studies have shown that the gene expression is predominantly found in morphologically differentiated neurologic cells. This gene is one of three alpha-tubulin genes in a cluster on chromosome 12q. Mutations in this gene cause lissencephaly type 3 (LIS3) - a neurological condition characterized by microcephaly, intellectual disability, and early-onset epilepsy caused by defective neuronal migration. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Jul 2017]

TUBA1B-AS1 (HGNC:56356): (TUBA1B antisense RNA 1)

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr12-49185576-G-A is described in Lovd as [Likely_pathogenic].
• PP2: Missense variant in the TUBA1A gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 163 curated pathogenic missense variants (we use a threshold of 10). The gene has 25 curated benign missense variants. Gene score misZ: 5.584 (above the threshold of 3.09). Trascript score misZ: 8.7455 (above the threshold of 3.09). GenCC associations: The gene is linked to tubulinopathy-associated dysgyria, intellectual disability, autosomal dominant 40, tubulinopathy, lissencephaly due to TUBA1A mutation.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.942

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBA1A	NM_006009.4	c.791G>T	p.Arg264Leu	missense_variant	Exon 4 of 4	ENST00000301071.12	NP_006000.2
TUBA1A	NM_001270399.2	c.791G>T	p.Arg264Leu	missense_variant	Exon 4 of 4		NP_001257328.1
TUBA1A	NM_001270400.2	c.686G>T	p.Arg229Leu	missense_variant	Exon 4 of 4		NP_001257329.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TUBA1A	ENST00000301071.12	c.791G>T	p.Arg264Leu	missense_variant	Exon 4 of 4	1	NM_006009.4	ENSP00000301071.7

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Dec 20, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 264 of the TUBA1A protein (p.Arg264Leu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TUBA1A-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. This variant disrupts the p.Arg264 amino acid residue in TUBA1A. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 17218254, 18199681, 27431206, 28677066, 29671837). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	D;D;.
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.85	.;T;T
M_CAP	Pathogenic	0.63	D
MetaRNN	Pathogenic	0.94	D;D;D
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Pathogenic	4.5	H;H;.
PrimateAI	Uncertain	0.72	T
PROVEAN	Pathogenic	-5.2	D;D;D
REVEL	Pathogenic	0.86
Sift	Pathogenic	0.0	D;D;.
Sift4G	Uncertain	0.0080	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.80
MutPred		0.76		Gain of catalytic residue at F267 (P = 8e-04);Gain of catalytic residue at F267 (P = 8e-04);.;
MVP		0.91
MPC		4.1
ClinPred		1.0	D
GERP RS		4.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.88
gMVP		1.0

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr12-49579358;