19-6494364-C-T

Position:

• chr19-6494364-C-T

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BS1_Supporting BS2

The NM_006087.4(TUBB4A):​c.*800G>A variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000546 in 146,548 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000055 (0 hom., cov: 30)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TUBB4A NM_006087.4 3_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: -1.88

Genes affected

TUBB4A (HGNC:20774): (tubulin beta 4A class IVa) This gene encodes a member of the beta tubulin family. Beta tubulins are one of two core protein families (alpha and beta tubulins) that heterodimerize and assemble to form microtubules. Mutations in this gene cause hypomyelinating leukodystrophy-6 and autosomal dominant torsion dystonia-4. Alternate splicing results in multiple transcript variants encoding different isoforms. A pseudogene of this gene is found on chromosome X. [provided by RefSeq, Jan 2014]

(HGNC:):

ACMG classification

Verdict is Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.92).
• BS1: Variant frequency is greater than expected in population amr. gnomad4 allele frequency = 0.0000546 (8/146548) while in subpopulation AMR AF= 0.000407 (6/14760). AF 95% confidence interval is 0.000177. There are 0 homozygotes in gnomad4. There are 2 alleles in male gnomad4 subpopulation. Median coverage is 30. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TUBB4A	NM_006087.4	c.*800G>A		3_prime_UTR_variant	4/4	ENST00000264071.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TUBB4A	ENST00000264071.7	c.*800G>A		3_prime_UTR_variant	4/4	1	NM_006087.4	P1
	ENST00000596027.1	n.45C>T		non_coding_transcript_exon_variant	1/2	5
	ENST00000599292.1	n.45C>T		non_coding_transcript_exon_variant	1/2	3

Frequencies

GnomAD3 genomes AF: 0.0000546 AC: 8 AN: 146548 Hom.: 0 Cov.: 30

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000407

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: 0.0000151

Gnomad OTH AF: 0.000491

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 100 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 62

Gnomad4 AFR exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

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 AF: 0.0000546 AC: 8 AN: 146548 Hom.: 0 Cov.: 30 AF XY: 0.0000280 AC XY: 2 AN XY: 71458

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000407

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000151

Gnomad4 OTH AF: 0.000491

Alfa AF: 0.000108 Hom.: 0

Bravo AF: 0.000193

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

Torsion dystonia 4 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 28, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Hypomyelinating leukodystrophy 6 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 28, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.92
CADD	Benign	0.11
DANN	Benign	0.47
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.2

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

LitVar

Other links and lift over

dbSNP: rs781702991; hg19: chr19-6494375;