Genetic Variant TUBB2B:p.Gly400Gly (chr6-3224889-G-A) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2BP4_StrongBP7

The NM_178012.5(TUBB2B):c.1200C>T(p.Gly400Gly) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000125 in 1,602,264 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.0000069 ( 0 hom., cov: 21)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

TUBB2B
NM_178012.5 synonymous

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.0170

Publications

0 publications found

Variant links:

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: Orphanet, Labcorp Genetics (formerly Invitae), G2P
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

TUBB2B links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.47).

BP7

Synonymous conserved (PhyloP=0.017 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_178012.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBB2B	NM_178012.5	MANE Select	c.1200C>T	p.Gly400Gly	synonymous	Exon 4 of 4	NP_821080.1	A0A384MEE3

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TUBB2B	ENST00000259818.8	TSL:1 MANE Select	c.1200C>T	p.Gly400Gly	synonymous	Exon 4 of 4	ENSP00000259818.6	Q9BVA1
TUBB2B	ENST00000473006.1	TSL:3	n.1317C>T		non_coding_transcript_exon	Exon 4 of 4
TUBB2B	ENST00000680070.1		n.2130C>T		non_coding_transcript_exon	Exon 3 of 3

Frequencies

GnomAD3 genomes

AF:

0.00000693

AC:

AN:

144348

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000260

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000404

AC:

AN:

247500

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000637

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.86e-7

AC:

AN:

1457916

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

725236

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33414

American (AMR)

AF:

0.00

AC:

AN:

44674

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26102

East Asian (EAS)

AF:

0.00

AC:

AN:

39678

South Asian (SAS)

AF:

0.00

AC:

AN:

86178

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51858

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4704

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111076

Other (OTH)

AF:

0.00

AC:

AN:

60232

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000693

AC:

AN:

144348

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

69808

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.0000260

AC:

AN:

38466

American (AMR)

AF:

0.00

AC:

AN:

14162

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3412

East Asian (EAS)

AF:

0.00

AC:

AN:

4920

South Asian (SAS)

AF:

0.00

AC:

AN:

4186

European-Finnish (FIN)

AF:

0.00

AC:

AN:

9754

Middle Eastern (MID)

AF:

0.00

AC:

AN:

304

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

66368

Other (OTH)

AF:

0.00

AC:

AN:

1888

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

ClinVar

ClinVar submissions

Significance:Uncertain significance

Revision:criteria provided, single submitter

View on ClinVar

Pathogenic

VUS

Benign

Condition

not specified (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.47

CADD

Benign

(source)

DANN

Benign

0.78

PhyloP100

0.017

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over