6-30722618-A-G

Variant names:

• chr6-30722618-A-G
• rs1776361528
• NM_178014.4:c.139A>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM2 PP2 PP5_Moderate BP4

The NM_178014.4(TUBB):​c.139A>G​(p.Ile47Val) 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 benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: TUBB NM_178014.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.50
• Publications: 0 publications found

Genes affected

TUBB (HGNC:20778): (tubulin beta class I) This gene encodes a beta tubulin protein. This protein forms a dimer with alpha tubulin and acts as a structural component of microtubules. Mutations in this gene cause cortical dysplasia, complex, with other brain malformations 6. Alternative splicing results in multiple splice variants. There are multiple pseudogenes for this gene on chromosomes 1, 6, 7, 8, 9, and 13. [provided by RefSeq, Jun 2014]

TUBB Gene-Disease associations (from GenCC):

• complex cortical dysplasia with other brain malformations 6

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• multiple benign circumferential skin creases on limbs 1

  Inheritance: AD Classification: DEFINITIVE, MODERATE Submitted by: Ambry Genetics, G2P
• TUBB3-related tubulinopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: Illumina
• multiple benign circumferential skin creases on limbs

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the TUBB gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 26 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 5.6252 (above the threshold of 3.09). Trascript score misZ: 8.3435 (above the threshold of 3.09). GenCC associations: The gene is linked to TUBB3-related tubulinopathy, multiple benign circumferential skin creases on limbs 1, complex cortical dysplasia with other brain malformations 6, multiple benign circumferential skin creases on limbs.
• PP5: Variant 6-30722618-A-G is Pathogenic according to our data. Variant chr6-30722618-A-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 976678.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP4: Computational evidence support a benign effect (MetaRNN=0.27045572). . Strength limited to SUPPORTING due to the PP5.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_178014.4. 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
	TUBB	NM_178014.4	MANE Select	c.139A>G	p.Ile47Val	missense	Exon 2 of 4	NP_821133.1	Q5SU16
	TUBB	NM_001293212.2		c.199A>G	p.Ile67Val	missense	Exon 2 of 4	NP_001280141.1
	TUBB	NM_001293213.2		c.139A>G	p.Ile47Val	missense	Exon 2 of 5	NP_001280142.1	B4DMJ5

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBB	ENST00000327892.13	TSL:1 MANE Select	c.139A>G	p.Ile47Val	missense	Exon 2 of 4	ENSP00000339001.7	P07437
	TUBB	ENST00000396389.5	TSL:5	c.85A>G	p.Ile29Val	missense	Exon 2 of 4	ENSP00000379672.1	Q5JP53
	TUBB	ENST00000940307.1		c.139A>G	p.Ile47Val	missense	Exon 2 of 3	ENSP00000610366.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
2	-	-	Complex cortical dysplasia with other brain malformations 6 (2)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.012	T
BayesDel_noAF	Benign	-0.26
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Benign	0.028	T
Eigen	Benign	0.083
Eigen_PC	Uncertain	0.23
FATHMM_MKL	Uncertain	0.91	D
M_CAP	Benign	0.071	D
MetaRNN	Benign	0.27	T
MetaSVM	Benign	-0.79	T
MutationAssessor	Benign	1.7	L
PhyloP100		7.5
PrimateAI	Pathogenic	0.89	D
PROVEAN	Benign	-0.34	N
REVEL	Benign	0.27
Sift4G	Benign	0.11	T
Polyphen		0.0	B
Vest4		0.29
MutPred		0.65		Gain of phosphorylation at Y51 (P = 0.0897)
MVP		0.60
MPC		1.6
ClinPred		0.93	D
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.47
gMVP		0.82
Mutation Taster		=65/35	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: rs1776361528; hg19: chr6-30690395;