rs794726855

Positions:

• chr15-43383359-A-AT

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_014444.5(TUBGCP4):​c.579dup​(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
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 0.398

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]

ACMG classification

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/exons	MANE	Protein	UniProt
TUBGCP4	NM_014444.5	c.579dup	p.Gly194TrpfsTer8	frameshift_variant	7/18	ENST00000564079.6	NP_055259.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TUBGCP4	ENST00000564079.6	c.579dup	p.Gly194TrpfsTer8	frameshift_variant	7/18	1	NM_014444.5	ENSP00000456648	A1

Frequencies

GnomAD3 genomes AF: 0.0000460 AC: 7 AN: 152200 Hom.: 0 Cov.: 32

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: 31 AN: 249472 Hom.: 0 AF XY: 0.000111 AC XY: 15 AN XY: 135348

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.: 0 Cov.: 31 AF XY: 0.0000701 AC XY: 51 AN XY: 727246

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: 7 AN: 152200 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74362

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.: 0

Bravo AF: 0.0000718

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephaly and chorioretinopathy 3 Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jul 12, 2023	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Apr 02, 2015	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Jul 26, 2016	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jun 13, 2023	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). For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 190124). 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. This variant is present in population databases (rs765297510, gnomAD 0.2%). -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Aug 24, 2023	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) -

Computational scores

Source: dbNSFP v4.3

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

Other links and lift over

dbSNP: rs794726855; hg19: chr15-43675557;