rs767399782

chr19-6495736-C-Achr19-6495736-C-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_006087.4(TUBB4A):c.763G>T(p.Val255Phe) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. V255I) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TUBB4A NM_006087.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.69

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]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 uncertain in NM_006087.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr19-6495736-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 217025.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=5, not_provided=1, Likely_pathogenic=2, Uncertain_significance=1}.
• PP2: Missense variant where missense usually causes diseases, TUBB4A
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.957

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TUBB4A	NM_006087.4	c.763G>T	p.Val255Phe	missense_variant	4/4	ENST00000264071.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TUBB4A	ENST00000264071.7	c.763G>T	p.Val255Phe	missense_variant	4/4	1	NM_006087.4	P1
TUBB4A	ENST00000594276.5	c.451G>T	p.Val151Phe	missense_variant	3/3	4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251186 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135838

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 6.84e-7 AC: 1 AN: 1461768 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727212

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ 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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
Cadd	Pathogenic	26
Dann	Uncertain	0.98
DEOGEN2	Benign	0.28	T;.
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.69
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	4.2	H;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-4.2	D;.
REVEL	Pathogenic	0.93
Sift4G	Uncertain	0.0090	D;D
Polyphen		1.0	D;.
Vest4		0.89
MutPred		0.80		Loss of catalytic residue at K252 (P = 0.1002);.;
MVP		0.89
MPC		3.2
ClinPred		0.99	D
GERP RS		4.0
Varity_R		0.99
gMVP		1.0

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: rs767399782; hg19: chr19-6495747;