22-50217760-G-GC

Variant names:

• chr22-50217760-G-GC
• NM_020461.4:c.5435_5436insG

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_020461.4(TUBGCP6):​c.5435_5436insG​(p.Phe1812LeufsTer19) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,794 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: TUBGCP6 NM_020461.4 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.13

Genes affected

TUBGCP6 (HGNC:18127): (tubulin gamma complex component 6) The protein encoded by this gene is part of a large multisubunit complex required for microtubule nucleation at the centrosome. [provided by RefSeq, Jul 2008]

SELENOO (HGNC:30395): (selenoprotein O) This gene encodes a selenoprotein that is localized to the mitochondria. It is the largest mammalian selenoprotein, containing the rare amino acid selenocysteine (Sec). Sec is encoded by the UGA codon, which normally signals translation termination. The 3' UTRs of selenoprotein mRNAs contain a conserved stem-loop structure, designated the Sec insertion sequence (SECIS) element, that is necessary for the recognition of UGA as a Sec codon, rather than as a stop signal. The exact function of this selenoprotein is not known, but it is thought to have redox activity. [provided by RefSeq, Dec 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.00458 CDS is truncated, and there are 1 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TUBGCP6	NM_020461.4	c.5435_5436insG	p.Phe1812LeufsTer19	frameshift_variant	Exon 25 of 25	ENST00000248846.10	NP_065194.3
SELENOO	NM_031454.2	c.*391_*392insC		downstream_gene_variant		ENST00000380903.7	NP_113642.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TUBGCP6	ENST00000248846.10	c.5435_5436insG	p.Phe1812LeufsTer19	frameshift_variant	Exon 25 of 25	1	NM_020461.4	ENSP00000248846.5
SELENOO	ENST00000380903.7	c.*391_*392insC		downstream_gene_variant		1	NM_031454.2	ENSP00000370288.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461794 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 727192

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Feb 03, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change results in a frameshift in the TUBGCP6 gene (p.Phe1812Leufs*19). While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 8 amino acid(s) of the TUBGCP6 protein and extend the protein by 10 additional amino acid residues. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with TUBGCP6-related conditions. ClinVar contains an entry for this variant (Variation ID: 1050928). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

Computational scores

Source: dbNSFP v4.3

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr22-50656189;