chr6-3224900-A-G

Variant names:

• chr6-3224900-A-G
• rs1057520787
• NM_178012.5:c.1189T>C

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PP2 PP3_Strong PP5_Moderate

The NM_178012.5(TUBB2B):​c.1189T>C​(p.Trp397Arg) 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 Pathogenic (★).

• Frequency: Genomes: not found (cov: 20)
• Consequence: TUBB2B NM_178012.5 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 8.95

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 Likely_pathogenic. Variant got 9 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.952
• PP5: Variant 6-3224900-A-G is Pathogenic according to our data. Variant chr6-3224900-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 379922.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr6-3224900-A-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBB2B	NM_178012.5	c.1189T>C	p.Trp397Arg	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.1189T>C	p.Trp397Arg	missense_variant	Exon 4 of 4	1	NM_178012.5	ENSP00000259818.6

Frequencies

GnomAD3 genomes Cov.: 20

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 20

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Jul 02, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); Missense variants in this gene are a common cause of disease and they are underrepresented in the general population; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 27010057) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.36
CADD	Uncertain	25
DANN	Benign	0.96
DEOGEN2	Uncertain	0.50	T
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.72	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Uncertain	0.44	D
MutationAssessor	Pathogenic	4.7	H
PrimateAI	Pathogenic	0.95	D
PROVEAN	Pathogenic	-6.9	D
REVEL	Pathogenic	0.90
Sift4G	Uncertain	0.0090	D
Polyphen		0.15	B
Vest4		0.89
MutPred		0.81		Gain of disorder (P = 0.0058);
MVP		0.90
ClinPred		1.0	D
GERP RS		5.1
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: rs1057520787; hg19: chr6-3225134;