rs864321677

Variant names:

• chr6-30723727-A-T
• rs864321677
• NM_178014.4:c.665A>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP2 PP5

The NM_178014.4(TUBB):​c.665A>T​(p.Tyr222Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (no stars). Synonymous variant affecting the same amino acid position (i.e. Y222Y) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: TUBB NM_178014.4 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 9.01
• Publications: 8 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: Ambry Genetics, G2P, 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

ENSG00000272540 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 0 uncertain in NM_178014.4
• 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 6-30723727-A-T is Pathogenic according to our data. Variant chr6-30723727-A-T is described in ClinVar as Pathogenic. ClinVar VariationId is 218926.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBB	NM_178014.4	c.665A>T	p.Tyr222Phe	missense_variant	Exon 4 of 4	ENST00000327892.13	NP_821133.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TUBB	ENST00000327892.13	c.665A>T	p.Tyr222Phe	missense_variant	Exon 4 of 4	1	NM_178014.4	ENSP00000339001.7

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Multiple benign circumferential skin creases on limbs 1 Pathogenic:1

Sep 11, 2023

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Uncertain	0.028	T
BayesDel_noAF	Benign	-0.20
CADD	Uncertain	23
DANN	Uncertain	0.98
DEOGEN2	Benign	0.23	T;.;T;.
Eigen	Uncertain	0.53
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Benign	0.028	D
MetaRNN	Uncertain	0.72	D;D;D;D
MetaSVM	Benign	-0.50	T
MutationAssessor	Benign	1.7	L;.;.;.
PhyloP100		9.0
PrimateAI	Pathogenic	0.84	D
PROVEAN	Uncertain	-3.1	D;D;D;D
REVEL	Uncertain	0.42
Sift4G	Benign	0.16	T;T;T;T
Polyphen		0.47	P;.;.;.
Vest4		0.75
MutPred		0.62		Loss of catalytic residue at L217 (P = 0.1155);.;.;.;
MVP		0.87
MPC		1.7
ClinPred		0.97	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.3
Varity_R		0.82
gMVP		0.96
Mutation Taster		=6/94	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: rs864321677; hg19: chr6-30691504;