16-47696411-G-T

Variant names:

• chr16-47696411-G-T
• rs199948078
• NM_000293.3:c.2926G>T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000293.3(PHKB):​c.2926G>T​(p.Glu976*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000687 in 1,456,580 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: not found (cov: 32)
  • Exomes 𝑓: 0.0000069 (0 hom.)
• Consequence: PHKB NM_000293.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 9.95
• Publications: 3 publications found

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 Gene-Disease associations (from GenCC):

• glycogen storage disease IXb

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, ClinGen, Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 12 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 16-47696411-G-T is Pathogenic according to our data. Variant chr16-47696411-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 242718.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PHKB	NM_000293.3	c.2926G>T	p.Glu976*	stop_gained	Exon 29 of 31	ENST00000323584.10	NP_000284.1
PHKB	NM_001363837.1	c.2926G>T	p.Glu976*	stop_gained	Exon 29 of 31		NP_001350766.1
PHKB	NM_001031835.3	c.2905G>T	p.Glu969*	stop_gained	Exon 30 of 32		NP_001027005.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PHKB	ENST00000323584.10	c.2926G>T	p.Glu976*	stop_gained	Exon 29 of 31	1	NM_000293.3	ENSP00000313504.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000199 AC: 5 AN: 251364 AF XY: 0.0000221

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000352

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.00000687 AC: 10 AN: 1456580 Hom.: 0 Cov.: 29 AF XY: 0.00000965 AC XY: 7 AN XY: 725026

African (AFR) AF: 0.00 AC: 0 AN: 33372

American (AMR) AF: 0.00 AC: 0 AN: 44702

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26110

East Asian (EAS) AF: 0.00 AC: 0 AN: 39680

South Asian (SAS) AF: 0.00 AC: 0 AN: 86160

European-Finnish (FIN) AF: 0.0000187 AC: 1 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000813 AC: 9 AN: 1107172

Other (OTH) AF: 0.00 AC: 0 AN: 60202

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000337 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.0000412 AC: 5

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Glycogen storage disease IXb Pathogenic:1

Sep 13, 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.Glu976*) 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 (rs199948078, gnomAD 0.004%). This variant has not been reported in the literature in individuals affected with PHKB-related conditions. For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.55	D
BayesDel_noAF	Pathogenic	0.66
CADD	Pathogenic	41
DANN	Uncertain	1.0
DEOGEN2	Benign	0.0	.;.;.
Eigen	Pathogenic	1.3
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.0	.;.;.
MetaRNN	Benign	0.0	.;.;.
MutationAssessor	Benign	0.0	.;.;.
PhyloP100		9.9
PROVEAN	Benign	0.0	.;.;.
REVEL	Benign	0.0
Sift	Pathogenic	0.0	.;.;.
Sift4G	Pathogenic	0.0	.;.;.
Vest4		0.49
GERP RS		5.5
PromoterAI		-0.037	Neutral
Mutation Taster		=1/199	disease causing (fs/PTC)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs199948078; hg19: chr16-47730322;