6-3225322-T-C

Position:

• chr6-3225322-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_178012.5(TUBB2B):​c.767A>G​(p.Asn256Ser) 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 Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 17)
• Consequence: TUBB2B NM_178012.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity no assertion criteria provided P:1 U:1
• Conservation: PhyloP100: 7.74

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 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TUBB2B. . Gene score misZ 5.1195 (greater than the threshold 3.09). Trascript score misZ 6.9522 (greater than threshold 3.09). GenCC has associacion of gene with 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, 0.964

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TUBB2B	NM_178012.5	c.767A>G	p.Asn256Ser	missense_variant	4/4	ENST00000259818.8	NP_821080.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TUBB2B	ENST00000259818.8	c.767A>G	p.Asn256Ser	missense_variant	4/4	1	NM_178012.5	ENSP00000259818	P1

Frequencies

GnomAD3 genomes Cov.: 17

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 17

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

Complex cortical dysplasia with other brain malformations 7 Pathogenic:1 Uncertain:1

Uncertain significance, no assertion criteria provided	clinical testing	Foundation for Research in Genetics and Endocrinology, FRIGE's Institute of Human Genetics	Nov 12, 2018	The observed variant c.767A>G (p.Asn256Ser) has not been reported in 1000 Genomes and ExAC databases. The in silico prediction of the given variant is possibly damaging by PolyPhen-2 and damaging by MutationTaster2, SIFT and LRT. -
Pathogenic, no assertion criteria provided	literature only	OMIM	Sep 01, 2012	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.55	D
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.37	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Uncertain	0.66	D
MutationAssessor	Pathogenic	3.0	M
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Uncertain	-4.3	D
REVEL	Pathogenic	0.86
Sift4G	Uncertain	0.014	D
Polyphen		0.77	P
Vest4		0.80
MutPred		0.89		Gain of methylation at K252 (P = 0.1161);
MVP		0.85
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.96
gMVP		0.98

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: rs397514568; hg19: chr6-3225556;