chr2-219271517-C-A

Variant names:

• chr2-219271517-C-A
• rs3731891
• NM_001355221.1:c.544C>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_001355221.1(TUBA4B):​c.544C>A​(p.Arg182Ser) 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 1,461,892 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.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: TUBA4B NM_001355221.1 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.08
• Publications: 2 publications found

Genes affected

TUBA4B (HGNC:18637): (tubulin alpha 4b) Predicted to enable GTP binding activity. Predicted to be a structural constituent of cytoskeleton. Predicted to be involved in microtubule cytoskeleton organization and mitotic cell cycle. Predicted to be active in cytoplasm and microtubule. [provided by Alliance of Genome Resources, Apr 2022]

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: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics, ClinGen
• autosomal dominant macrothrombocytopenia

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.836

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001355221.1. 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
	TUBA4B	NM_001355221.1	MANE Select	c.544C>A	p.Arg182Ser	missense	Exon 4 of 4	NP_001342150.1	Q9H853

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TUBA4B	ENST00000490341.3	TSL:2 MANE Select	c.544C>A	p.Arg182Ser	missense	Exon 4 of 4	ENSP00000487719.1	Q9H853
	TUBA4B	ENST00000473885.5	TSL:1	n.632C>A		non_coding_transcript_exon	Exon 4 of 4
	TUBA4B	ENST00000485041.5	TSL:1	n.637C>A		non_coding_transcript_exon	Exon 4 of 4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251416 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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461892 Hom.: 0 Cov.: 68 AF XY: 0.00000138 AC XY: 1 AN XY: 727248

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: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

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

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.36
BayesDel_noAF	Benign	-0.44
CADD	Benign	18
DANN	Benign	0.84
DEOGEN2	Benign	0.31	T
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Uncertain	0.96	D
MetaRNN	Pathogenic	0.84	D
PhyloP100		1.1
PrimateAI	Uncertain	0.61	T
Sift4G	Pathogenic	0.0	D
Polyphen		0.95	P
Vest4		0.85
GERP RS		2.7
Varity_R		0.10
gMVP		0.40
Mutation Taster		=100/0	polymorphism

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: rs3731891; hg19: chr2-220136239;