6-3224781-G-T

Variant names:

• chr6-3224781-G-T
• rs746506962
• NM_178012.5:c.1308C>A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_178012.5(TUBB2B):​c.1308C>A​(p.Phe436Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,732 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TUBB2B NM_178012.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.358

Genes affected

TUBB2B (HGNC:30829): (tubulin beta 2B class IIb) The protein encoded by this gene is a beta isoform of tubulin, which binds GTP and is a major component of microtubules. This gene is highly similar to TUBB2A and TUBB2C. Defects in this gene are a cause of asymmetric polymicrogyria. [provided by RefSeq, Mar 2010]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the TUBB2B gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 45 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 5.1195 (above the threshold of 3.09). Trascript score misZ: 6.9522 (above the threshold of 3.09). GenCC associations: The gene is linked to tubulinopathy-associated dysgyria, congenital fibrosis of extraocular muscles, cerebellar ataxia, intellectual disability, and dysequilibrium, complex cortical dysplasia with other brain malformations 7, complex cortical dysplasia with other brain malformations.
• BP4: Computational evidence support a benign effect (MetaRNN=0.16333443).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBB2B	NM_178012.5	c.1308C>A	p.Phe436Leu	missense_variant	Exon 4 of 4	ENST00000259818.8	NP_821080.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TUBB2B	ENST00000259818.8	c.1308C>A	p.Phe436Leu	missense_variant	Exon 4 of 4	1	NM_178012.5	ENSP00000259818.6

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461732 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727162

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.81
BayesDel_addAF	Benign	-0.036	T
BayesDel_noAF	Benign	-0.29
CADD	Benign	21
DANN	Benign	0.93
DEOGEN2	Benign	0.16	T
Eigen	Benign	-0.68
Eigen_PC	Benign	-0.61
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Uncertain	0.95	D
M_CAP	Benign	0.041	D
MetaRNN	Benign	0.16	T
MetaSVM	Benign	-0.95	T
MutationAssessor	Benign	0.90	L
PrimateAI	Uncertain	0.77	T
PROVEAN	Benign	-1.0	N
REVEL	Benign	0.14
Sift4G	Benign	0.37	T
Polyphen		0.29	B
Vest4		0.38
MutPred		0.20		Gain of helix (P = 0.0854);
MVP		0.29
ClinPred		0.29	T
GERP RS		-3.2
Varity_R		0.38
gMVP		0.87

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: rs746506962; hg19: chr6-3225015;