chr20-59019526-C-G

Variant names:

• chr20-59019526-C-G
• rs754294863
• NM_030773.4:c.4C>G

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_030773.4(TUBB1):​c.4C>G​(p.Arg2Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,860 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R2P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TUBB1 NM_030773.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.01
• Publications: 0 publications found

Genes affected

TUBB1 (HGNC:16257): (tubulin beta 1 class VI) This gene encodes a member of the beta tubulin protein family. Beta tubulins are one of two core protein families (alpha and beta tubulins) that heterodimerize and assemble to form microtubules. This protein is specifically expressed in platelets and megakaryocytes and may be involved in proplatelet production and platelet release. A mutations in this gene is associated with autosomal dominant macrothrombocytopenia. Two pseudogenes of this gene are found on chromosome Y.[provided by RefSeq, Jul 2010]

TUBB1 Gene-Disease associations (from GenCC):

• macrothrombocytopenia, isolated, 1, autosomal dominant

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Illumina, ClinGen, Labcorp Genetics (formerly Invitae)
• autosomal dominant macrothrombocytopenia

  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
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.848

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_030773.4. 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
	TUBB1	NM_030773.4	MANE Select	c.4C>G	p.Arg2Gly	missense	Exon 1 of 4	NP_110400.1	Q9H4B7

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBB1	ENST00000217133.2	TSL:1 MANE Select	c.4C>G	p.Arg2Gly	missense	Exon 1 of 4	ENSP00000217133.1	Q9H4B7

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251432 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

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: 6.84e-7 AC: 1 AN: 1461860 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727230

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111994

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.79
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Pathogenic	0.19
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.22	T
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.47
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Uncertain	0.18	D
MetaRNN	Pathogenic	0.85	D
MetaSVM	Uncertain	0.29	D
MutationAssessor	Uncertain	2.2	M
PhyloP100		1.0
PrimateAI	Pathogenic	0.85	D
PROVEAN	Benign	-1.7	N
REVEL	Pathogenic	0.69
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.028	D
Polyphen		1.0	D
Vest4		0.84
MutPred		0.51		Loss of sheet (P = 0.0457)
MVP		0.85
MPC		0.84
ClinPred		0.92	D
GERP RS		4.0
PromoterAI		-0.030	Neutral
Varity_R		0.37
gMVP		0.84
Mutation Taster		=31/69	disease causing

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: rs754294863; hg19: chr20-57594581;