NM_178012.5:c.859C>T

Variant names:

• chr6-3225230-G-A
• rs587784501
• NM_178012.5:c.859C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP2 PP3

The NM_178012.5(TUBB2B):​c.859C>T​(p.Pro287Ser) 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 12)
• Consequence: TUBB2B NM_178012.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.60
• Publications: 1 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 6 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 1 uncertain in NM_178012.5
• 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, 0.818

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBB2B	NM_178012.5	c.859C>T	p.Pro287Ser	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.859C>T	p.Pro287Ser	missense_variant	Exon 4 of 4	1	NM_178012.5	ENSP00000259818.6

Frequencies

GnomAD3 genomes Cov.: 12

GnomAD4 exome Cov.: 21

GnomAD4 genome Cov.: 12

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Complex cortical dysplasia with other brain malformations 7 Uncertain:1

Dec 24, 2013

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
BayesDel_addAF	Pathogenic	0.22	D
BayesDel_noAF	Uncertain	0.070
CADD	Uncertain	23
DANN	Benign	0.94
DEOGEN2	Uncertain	0.67	D
Eigen	Benign	0.18
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.52	T
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.82	D
MetaSVM	Benign	-0.46	T
MutationAssessor	Benign	1.0	L
PhyloP100		9.6
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-5.2	D
REVEL	Pathogenic	0.68
Sift4G	Benign	0.23	T
Polyphen		0.0	B
Vest4		0.68
MutPred		0.57		Gain of disorder (P = 0.1379);
MVP		0.75
ClinPred		0.94	D
GERP RS		5.0
Varity_R		0.87
gMVP		0.76
Mutation Taster		=24/76	disease causing

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: rs587784501; hg19: chr6-3225464;