rs121918021

Positions:

Variant summary

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

The NM_000293.3(PHKB):c.1257T>A(p.Tyr419*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00011 in 1,612,040 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00011 ( 0 hom. )

Consequence

PHKB
NM_000293.3 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:4

Conservation

PhyloP100: 0.510

Variant links:

Genes affected

PHKB (HGNC:8927): (phosphorylase kinase regulatory subunit beta) 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, encoded by this gene, which is a member of the phosphorylase b kinase regulatory subunit family. The gamma subunit also includes the skeletal muscle and hepatic isoforms, encoded by two different genes. 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 9B, also known as phosphorylase kinase deficiency of liver and muscle. Alternatively spliced transcript variants encoding different isoforms have been identified in this gene. Two pseudogenes have been found on chromosomes 14 and 20, respectively.[provided by RefSeq, Feb 2010]

PHKB links:

PHKB (HGNC:):

PHKB 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 16-47596425-T-A is Pathogenic according to our data. Variant chr16-47596425-T-A is described in ClinVar as [Pathogenic]. Clinvar id is 13620.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr16-47596425-T-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PHKB	NM_000293.3 linkuse as main transcript	c.1257T>A	p.Tyr419*	stop_gained	13/31	ENST00000323584.10	NP_000284.1	Q93100-1
PHKB	NM_001363837.1 linkuse as main transcript	c.1257T>A	p.Tyr419*	stop_gained	13/31		NP_001350766.1
PHKB	NM_001031835.3 linkuse as main transcript	c.1236T>A	p.Tyr412*	stop_gained	14/32		NP_001027005.1	Q93100-4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PHKB	ENST00000323584.10 linkuse as main transcript	c.1257T>A	p.Tyr419*	stop_gained	13/31	1	NM_000293.3	ENSP00000313504.5		Q93100-1

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152160

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000597

AC:

AN:

251360

Hom.:

AF XY:

0.0000442

AC XY:

AN XY:

135860

show subpopulations

Gnomad AFR exome

AF:

0.0000616

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:

0.000123

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000114

AC:

167

AN:

1459880

Hom.:

Cov.:

AF XY:

0.000100

AC XY:

AN XY:

726440

show subpopulations

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:

0.000145

Gnomad4 OTH exome

AF:

0.0000995

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152160

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74336

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000655

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000135

Hom.:

Bravo

AF:

0.0000869

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000576

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.000415

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Glycogen storage disease IXb

Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	Jul 01, 1997	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 04, 2023	This sequence change creates a premature translational stop signal (p.Tyr419*) in the PHKB gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PHKB are known to be pathogenic (PMID: 9215682, 9326319). This variant is present in population databases (rs121918021, gnomAD 0.01%). This premature translational stop signal has been observed in individual(s) with glycogen storage disease (PMID: 9215682). This variant is also known as Y418ter. ClinVar contains an entry for this variant (Variation ID: 13620). For these reasons, this variant has been classified as Pathogenic. -

Glycogen phosphorylase kinase deficiency

Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

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

Feb 08, 2024

Variant summary: PHKB c.1257T>A (p.Tyr419X) 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 6e-05 in 251360 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in PHKB causing Glycogen Phosphorylase Kinase Deficiency (6e-05 vs 0.0011), allowing no conclusion about variant significance. c.1257T>A has been reported in the literature in at least one compound heterozygous individual affected with Glycogen Phosphorylase Kinase Deficiency (e.g. Burwinkel_1997). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 9215682). ClinVar contains an entry for this variant (Variation ID: 13620). Based on the evidence outlined above, the variant was classified as pathogenic. -

PHKB-related disorder

Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Mar 29, 2024

The PHKB c.1236T>A variant is predicted to result in premature protein termination (p.Tyr412*). This variant, which is also described as c.1257T>A using alternate transcript NM_000293.2, has been reported in the compound heterozygous state with a second causative PHKB variant in two unrelated patients with glycogen storage disease type IXb (GSD IXb) (Burwinkel et al. 1997. PubMed ID: 9402963, referred to as Y418ter; Beauchamp et al. 2007. PubMed ID: 17689125). This variant is reported in 0.012% of alleles in individuals of European (Non-Finnish) descent in gnomAD. Other premature protein termination variants in PHKB both up- and downstream of this variant have been reported to be causative of GSD IXb (Human Gene Mutation Database). This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.46

BayesDel_noAF

Pathogenic

0.33

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Uncertain

0.36

Eigen_PC

Benign

0.14

FATHMM_MKL

Benign

0.47

Vest4

0.50

GERP RS

1.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

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

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