16-30748871-CAA-C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000294.3(PHKG2):c.53_54del(p.Lys18ArgfsTer9) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 30)
• Consequence: PHKG2 NM_000294.3 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.95

Genes affected

PHKG2 (HGNC:8931): (phosphorylase kinase catalytic subunit gamma 2) Phosphorylase kinase is a polymer of 16 subunits, four each of alpha, beta, gamma and delta. The alpha subunit includes the skeletal muscle and hepatic isoforms, encoded by two different genes. The beta subunit is the same in both the muscle and hepatic isoforms, and encoded by one gene. The gamma subunit also includes the skeletal muscle and hepatic isoforms, and the hepatic isoform is encoded by this gene. The delta subunit is a calmodulin and can be encoded by three different genes. The gamma subunits contain the active site of the enzyme, whereas the alpha and beta subunits have regulatory functions controlled by phosphorylation. The delta subunit mediates the dependence of the enzyme on calcium concentration. Mutations in this gene cause glycogen storage disease type 9C, also known as autosomal liver glycogenosis. Alternatively spliced transcript variants encoding different isoforms have been identified in this gene.[provided by RefSeq, Feb 2010]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 41 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-30748871-CAA-C is Pathogenic according to our data. Variant chr16-30748871-CAA-C is described in ClinVar as [Pathogenic]. Clinvar id is 2834443.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PHKG2	NM_000294.3	c.53_54del	p.Lys18ArgfsTer9	frameshift_variant	2/10	ENST00000563588.6
PHKG2	NM_001172432.2	c.53_54del	p.Lys18ArgfsTer9	frameshift_variant	2/11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PHKG2	ENST00000563588.6	c.53_54del	p.Lys18ArgfsTer9	frameshift_variant	2/10	1	NM_000294.3	P4

Frequencies

GnomAD3 genomes Cov.: 30

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 30

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Glycogen storage disease IXc Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Feb 15, 2023

For these reasons, this variant has been classified as Pathogenic. This sequence change creates a premature translational stop signal (p.Lys18Argfs*9) in the PHKG2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PHKG2 are known to be pathogenic (PMID: 8896567, 17689125, 21646031). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with PHKG2-related conditions. -

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: chr16-30760192;