6-3153907-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_001069.3(TUBB2A):c.1294G>C(p.Glu432Gln) 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 benign 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. E432K) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TUBB2A NM_001069.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.75

Genes affected

TUBB2A (HGNC:12412): (tubulin beta 2A class IIa) Microtubules, key participants in processes such as mitosis and intracellular transport, are composed of heterodimers of alpha- and beta-tubulins. The protein encoded by this gene is a beta-tubulin. Defects in this gene are associated with complex cortical dysplasia with other brain malformations-5. Two transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Jul 2015]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, TUBB2A
• BP4: Computational evidence support a benign effect (MetaRNN=0.27916926).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TUBB2A	NM_001069.3	c.1294G>C	p.Glu432Gln	missense_variant	4/4	ENST00000333628.4
TUBB2A	NM_001310315.2	c.1039G>C	p.Glu347Gln	missense_variant	4/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TUBB2A	ENST00000333628.4	c.1294G>C	p.Glu432Gln	missense_variant	4/4	1	NM_001069.3	P1

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251348 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135834

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 6.84e-7 AC: 1 AN: 1461724 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727146

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 30

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 17, 2023

This sequence change replaces glutamic acid, which is acidic and polar, with glutamine, which is neutral and polar, at codon 432 of the TUBB2A protein (p.Glu432Gln). This variant is present in population databases (no rsID available, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with TUBB2A-related conditions. ClinVar contains an entry for this variant (Variation ID: 1390679). 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 not expected to disrupt TUBB2A protein function. 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	Uncertain	0.41
BayesDel_addAF	Uncertain	0.15	D
BayesDel_noAF	Uncertain	-0.020
Cadd	Uncertain	24
Dann	Uncertain	0.98
DEOGEN2	Benign	0.22	T
Eigen	Uncertain	0.33
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Uncertain	0.088	D
MetaRNN	Benign	0.28	T
MetaSVM	Benign	-0.41	T
MutationAssessor	Uncertain	2.2	M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.74	T
PROVEAN	Benign	-0.71	N
REVEL	Uncertain	0.40
Sift4G	Benign	0.095	T
Polyphen		0.50	P
Vest4		0.35
MutPred		0.11		Gain of helix (P = 0.0425);
MVP		0.80
ClinPred		0.78	D
GERP RS		5.0
Varity_R		0.42
gMVP		0.91

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: rs1345424333; hg19: chr6-3154141;