Variant chr22-18110870-T-G details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PVS1_Moderate

The NM_018943.3(TUBA8):c.3+2T>G variant causes a splice donor change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000115 in 1,395,500 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

TUBA8
NM_018943.3 splice_donor

Scores

Splicing: ADA: 1.000

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.49

Variant links:

Genes affected

TUBA8 (HGNC:12410): (tubulin alpha 8) This gene encodes a member of the alpha tubulin protein family. Alpha tubulins are one of two core protein families (alpha and beta tubulins) that heterodimerize and assemble to form microtubules. Mutations in this gene are associated with polymicrogyria and optic nerve hypoplasia. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Jul 2010]

TUBA8 links:

(HGNC:):

links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.043703705 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.5, offset of -29, new splice context is: gagGTgcgc. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TUBA8	NM_018943.3 linkuse as main transcript	c.3+2T>G		splice_donor_variant		ENST00000330423.8	NP_061816.1
TUBA8	NM_001193414.2 linkuse as main transcript	c.-196+31T>G		intron_variant			NP_001180343.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TUBA8	ENST00000330423.8 linkuse as main transcript	c.3+2T>G		splice_donor_variant		1	NM_018943.3	ENSP00000333326	P1	Q9NY65-1
	ENST00000623543.1 linkuse as main transcript	n.20285A>C		non_coding_transcript_exon_variant	1/1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000263

AC:

AN:

152138

Hom.:

AF XY:

0.0000243

AC XY:

AN XY:

82306

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000320

Gnomad SAS 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:

0.0000115

AC:

AN:

1395500

Hom.:

Cov.:

AF XY:

0.0000101

AC XY:

AN XY:

689672

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000431

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Bravo

AF:

0.0000189

ExAC

AF:

0.0000464

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 03, 2021

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with TUBA8-related conditions. This variant is present in population databases (rs775244571, ExAC 0.3%). This sequence change affects a donor splice site in intron 1 of the TUBA8 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), however the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in TUBA8 cause disease. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Uncertain

0.083

BayesDel_noAF

Pathogenic

0.19

CADD

Pathogenic

DANN

Uncertain

0.98

Eigen

Pathogenic

0.79

Eigen_PC

Uncertain

0.59

FATHMM_MKL

Benign

0.44

MutationTaster

Benign

1.0

D;D

GERP RS

4.1

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

0.98

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.61

Position offset: -31

DS_DL_spliceai

0.98

Position offset: -2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over