Genetic Variant NM_020778.5:c.-66delG (chr15-84817382-CG-C) – ACMG Classification: Uncertain_significance (1 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2BS1_Supporting

The NM_020778.5(ALPK3):c.-66delG variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000443 in 1,218,986 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.00024 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000017 ( 0 hom. )

Consequence

ALPK3
NM_020778.5 5_prime_UTR

Scores

Not classified

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts P:1U:2

Conservation

PhyloP100: 0.796

Variant links:

Genes affected

ALPK3 (HGNC:17574): (alpha kinase 3) Predicted to enable ATP binding activity; protein serine kinase activity; and protein serine/threonine kinase activity. Predicted to be involved in cardiac muscle cell development. Predicted to be active in nucleus. Implicated in hypertrophic cardiomyopathy. [provided by Alliance of Genome Resources, Apr 2022]

ALPK3 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000239 (36/150698) while in subpopulation AFR AF= 0.000702 (29/41314). AF 95% confidence interval is 0.000501. There are 0 homozygotes in gnomad4. There are 15 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ALPK3	NM_020778.5 link	c.-66delG		5_prime_UTR_variant	Exon 1 of 14	ENST00000258888.6	NP_065829.4	Q96L96

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ALPK3	ENST00000258888 link	c.-66delG		5_prime_UTR_variant	Exon 1 of 14	1	NM_020778.5	ENSP00000258888.6		Q96L96

Frequencies

GnomAD3 genomes

AF:

0.000239

AC:

AN:

150594

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000704

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000661

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.0160

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.000484

GnomAD4 exome

AF:

0.0000168

AC:

AN:

1068288

Hom.:

Cov.:

AF XY:

0.0000277

AC XY:

AN XY:

505556

show subpopulations

Gnomad4 AFR exome

AF:

0.000679

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:

0.00000109

Gnomad4 OTH exome

AF:

0.0000471

GnomAD4 genome

AF:

0.000239

AC:

AN:

150698

Hom.:

Cov.:

AF XY:

0.000204

AC XY:

AN XY:

73642

show subpopulations

Gnomad4 AFR

AF:

0.000702

Gnomad4 AMR

AF:

0.0000660

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000479

Alfa

AF:

0.000142

Hom.:

Bravo

AF:

0.000193

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cardiomyopathy, familial hypertrophic 27

Pathogenic:1

Feb 20, 2025

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

not provided

Uncertain:1

Dec 16, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ala181Profs*130) in the ALPK3 gene. It is unclear whether it will result in an absent or disrupted protein product because an in-frame methionine located at codon 203 has the potential to rescue this truncating variant. This variant is present in population databases (no rsID available, gnomAD 0.06%). This premature translational stop signal has been observed in individual(s) with clinical features of ALPK3-related conditions (PMID: 32480058). ClinVar contains an entry for this variant (Variation ID: 1487747). 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. -

Cardiovascular phenotype

Uncertain:1

Nov 28, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.541delG variant, located in coding exon 1 of the ALPK3 gene, results from a deletion of one nucleotide at nucleotide position 541, causing a translational frameshift with a predicted alternate stop codon (p.A181Pfs*130). This variant was reported in one individual with dilated cardiomyopathy, who had a second ALPK3 variant also detected; however, phase information was not provided (Herkert JC et al. Am Heart J, 2020 07;225:108-119). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. However, based on data from gnomAD, several loss of function alterations in the first exon of ALPK3 (p.C64* and p.E148Qfs*8) are too frequent to cause disease given the incidence of pediatric cardiomyopathy. The abundance of nonsense and frameshift alleles in the first exon in population databases brings into question the pathogenicity of loss of function alterations in N-terminus of ALPK3 and suggests the possibility of an alternative start site. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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