Genetic Variant NM_006000.3:c.958C>T (chr2-219250741-G-A) – ACMG Classification: Uncertain_significance (5 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 9P and 4B. PM5PP2PP3_StrongPP5_ModerateBS2

The NM_006000.3(TUBA4A):c.958C>T(p.Arg320Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000496 in 1,614,118 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R320H) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

TUBA4A
NM_006000.3 missense

Scores

Clinical Significance

Likely pathogenic criteria provided, single submitter P:2

Conservation

PhyloP100: 8.02

Publications

15 publications found

Variant links:

Genes affected

TUBA4A (HGNC:12407): (tubulin alpha 4a) Microtubules of the eukaryotic cytoskeleton perform essential and diverse functions and are composed of a heterodimer of alpha and beta tubulin. The genes encoding these microtubule constituents are part of the tubulin superfamily, which is composed of six distinct families. Genes from the alpha, beta and gamma tubulin families are found in all eukaryotes. The alpha and beta tubulins represent the major components of microtubules, while gamma tubulin plays a critical role in the nucleation of microtubule assembly. There are multiple alpha and beta tubulin genes and they are highly conserved among and between species. This gene encodes an alpha tubulin that is a highly conserved homolog of a rat testis-specific alpha tubulin. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jun 2013]

TUBA4A Gene-Disease associations (from GenCC):

amyotrophic lateral sclerosis type 22
Inheritance: AD, Unknown Classification: MODERATE, LIMITED Submitted by: ClinGen, Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
autosomal dominant macrothrombocytopenia
Inheritance: AD Classification: LIMITED Submitted by: ClinGen

TUBA4A links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

PM5

Other missense variant is known to change same aminoacid residue: Variant chr2-219250740-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 180183.Status of the report is no_assertion_criteria_provided, 0 stars.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 6 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 3.3027 (above the threshold of 3.09). Trascript score misZ: 4.9936 (above the threshold of 3.09). GenCC associations: The gene is linked to autosomal dominant macrothrombocytopenia, amyotrophic lateral sclerosis type 22.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.974

PP5

Variant 2-219250741-G-A is Pathogenic according to our data. Variant chr2-219250741-G-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 180182.Status of the report is criteria_provided_single_submitter, 1 stars.

BS2

High AC in GnomAdExome4 at 7 AD,Unknown gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006000.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBA4A	NM_006000.3	MANE Select	c.958C>T	p.Arg320Cys	missense	Exon 4 of 4	NP_005991.1
	TUBA4A	NM_001278552.2		c.913C>T	p.Arg305Cys	missense	Exon 4 of 4	NP_001265481.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TUBA4A	ENST00000248437.9	TSL:1 MANE Select	c.958C>T	p.Arg320Cys	missense	Exon 4 of 4	ENSP00000248437.4
TUBA4A	ENST00000392088.6	TSL:2	c.913C>T	p.Arg305Cys	missense	Exon 4 of 4	ENSP00000375938.2
TUBA4A	ENST00000498660.1	TSL:3	n.778C>T		non_coding_transcript_exon	Exon 3 of 3

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152226

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000795

AC:

AN:

251488

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000479

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727246

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000450

AC:

AN:

1112010

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.461

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:

0.00000657

AC:

AN:

152226

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74350

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41460

American (AMR)

AF:

0.00

AC:

AN:

15280

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5200

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10616

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68046

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00

Hom.:

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Amyotrophic lateral sclerosis type 22

Pathogenic:1

Oct 22, 2014

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

not provided

Pathogenic:1

May 09, 2023

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Published functional studies demonstrate a damaging effect on protein binding (Smith et al., 214; Ganne et al., 2023); This variant is associated with the following publications: (PMID: 26465396, 31585128, 31574570, 28412269, 25374358, 33378215, 34830115, 34169147, 36747013)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.32

BayesDel_noAF

Pathogenic

0.30

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.92

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.92

FATHMM_MKL

Uncertain

0.97

LIST_S2

Uncertain

0.89

M_CAP

Pathogenic

0.82

MetaRNN

Pathogenic

0.97

MetaSVM

Pathogenic

0.96

MutationAssessor

Pathogenic

4.4

PhyloP100

8.0

PrimateAI

Pathogenic

0.88

PROVEAN

Pathogenic

-6.2

REVEL

Pathogenic

0.97

Sift4G

Uncertain

0.050

Polyphen

0.92

Vest4

0.83

MutPred

0.88

Gain of sheet (P = 0.0827)

MVP

0.95

MPC

2.5

ClinPred

0.96

GERP RS

5.3

Varity_R

0.69

gMVP

0.97

Mutation Taster

=2/98

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over