Genetic Variant NM_014444.5:c.579dupT (chr15-43383359-A-AT) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_014444.5(TUBGCP4):c.579dupT(p.Gly194TrpfsTer8) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000712 in 1,614,080 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000074 ( 0 hom. )

Consequence

TUBGCP4
NM_014444.5 frameshift

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6

Conservation

PhyloP100: 0.398

Variant links:

Genes affected

TUBGCP4 (HGNC:16691): (tubulin gamma complex component 4) This gene encodes a component of the gamma-tubulin ring complex, which is required for microtubule nucleation. In mammalian cells, the protein localizes to centrosomes in association with gamma-tubulin. Crystal structure analysis revealed a structure composed of five helical bundles arranged around conserved hydrophobic cores. An exposed surface area located in the C-terminal domain is essential and sufficient for direct binding to gamma-tubulin. Mutations in this gene that alter microtubule organization are associated with microcephaly and chorioretinopathy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, May 2015]

TUBGCP4 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 15-43383359-A-AT is Pathogenic according to our data. Variant chr15-43383359-A-AT is described in ClinVar as [Likely_pathogenic]. Clinvar id is 190124.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBGCP4	NM_014444.5 link	c.579dupT	p.Gly194TrpfsTer8	frameshift_variant	Exon 7 of 18	ENST00000564079.6	NP_055259.2	Q9UGJ1-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TUBGCP4	ENST00000564079.6 link	c.579dupT	p.Gly194TrpfsTer8	frameshift_variant	Exon 7 of 18	1	NM_014444.5	ENSP00000456648.2		Q9UGJ1-2

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152200

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00144

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.000124

AC:

AN:

249472

Hom.:

AF XY:

0.000111

AC XY:

AN XY:

135348

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00248

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000442

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000739

AC:

108

AN:

1461880

Hom.:

Cov.:

AF XY:

0.0000701

AC XY:

AN XY:

727246

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00264

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000198

Gnomad4 OTH exome

AF:

0.000281

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152200

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74362

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00144

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.000478

Alfa

AF:

0.000477

Hom.:

Bravo

AF:

0.0000718

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Microcephaly and chorioretinopathy 3

Pathogenic:4

Apr 02, 2015

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Sep 25, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TUBGCP4 c.579dupT (p.Gly194TrpfsX8) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 0.00012 in 249472 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in TUBGCP4 causing Microcephaly And Chorioretinopathy 3, allowing no conclusion about variant significance. c.579dupT has been reported in the literature in two compound heterozygous individuals in a family affected with Microcephaly And Chorioretinopathy 3 (Scheidecker_2015). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 25817018). ClinVar contains an entry for this variant (Variation ID: 190124). Based on the evidence outlined above, the variant was classified as pathogenic. -

Jul 12, 2023

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jul 26, 2016

Genetic Services Laboratory, University of Chicago

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Pathogenic:2

Aug 24, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 34313030, 25817018) -

Nov 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gly194Trpfs*8) in the TUBGCP4 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in TUBGCP4 are known to be pathogenic (PMID: 25817018). This variant is present in population databases (rs765297510, gnomAD 0.2%). This premature translational stop signal has been observed in individual(s) with clinical features of microcephaly and chorioretinal dysplasia (PMID: 25817018). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 190124). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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

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