rs878853284

Variant names:

• chr6-3225373-C-A
• rs878853284
• NM_178012.5:c.716G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP2 PP3_Moderate PP5

The ENST00000259818.8(TUBB2B):​c.716G>T​(p.Cys239Phe) 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 Pathogenic (no stars).

• Frequency: Genomes: not found (cov: 28)
• Consequence: TUBB2B ENST00000259818.8 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 5.98
• Publications: 4 publications found

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]

TUBB2B Gene-Disease associations (from GenCC):

• complex cortical dysplasia with other brain malformations

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• complex cortical dysplasia with other brain malformations 7

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Orphanet
• congenital fibrosis of extraocular muscles

  Inheritance: AD Classification: SUPPORTIVE, LIMITED Submitted by: Orphanet, Genomics England PanelApp
• tubulinopathy-associated dysgyria

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• cerebellar ataxia, intellectual disability, and dysequilibrium

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 2 uncertain in ENST00000259818.8
• 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, complex cortical dysplasia with other brain malformations 7, complex cortical dysplasia with other brain malformations, cerebellar ataxia, intellectual disability, and dysequilibrium.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.895
• PP5: Variant 6-3225373-C-A is Pathogenic according to our data. Variant chr6-3225373-C-A is described in ClinVar as Pathogenic. ClinVar VariationId is 236255.Status of the report is no_assertion_criteria_provided, 0 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: ENST00000259818.8. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBB2B	NM_178012.5	MANE Select	c.716G>T	p.Cys239Phe	missense	Exon 4 of 4	NP_821080.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBB2B	ENST00000259818.8	TSL:1 MANE Select	c.716G>T	p.Cys239Phe	missense	Exon 4 of 4	ENSP00000259818.6
	TUBB2B	ENST00000473006.1	TSL:3	n.833G>T		non_coding_transcript_exon	Exon 4 of 4
	TUBB2B	ENST00000680070.1		n.1646G>T		non_coding_transcript_exon	Exon 3 of 3

Frequencies

GnomAD3 genomes Cov.: 28

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 28

ClinVar

ClinVar submissions as Germline

Significance: Pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Complex cortical dysplasia with other brain malformations 7 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.27
CADD	Pathogenic	26
DANN	Benign	0.97
DEOGEN2	Uncertain	0.49	T
Eigen	Uncertain	0.40
Eigen_PC	Uncertain	0.38
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.62	T
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Uncertain	-0.15	T
MutationAssessor	Uncertain	2.8	M
PhyloP100		6.0
PrimateAI	Pathogenic	0.88	D
PROVEAN	Pathogenic	-8.0	D
REVEL	Pathogenic	0.87
Sift4G	Benign	0.082	T
Polyphen		0.0090	B
Vest4		0.97
MutPred		0.69		Loss of catalytic residue at L240 (P = 0.1509)
MVP		0.70
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.96
gMVP		0.98
Mutation Taster		=8/92	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs878853284; hg19: chr6-3225607;