8-43122848-A-C

Variant names:

• chr8-43122848-A-C
• rs762404960
• NM_032237.5:c.1024A>C

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_032237.5(POMK):​c.1024A>C​(p.Met342Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,450 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M342V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: POMK NM_032237.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.34
• Publications: 0 publications found

Genes affected

POMK (HGNC:26267): (protein O-mannose kinase) This gene encodes a protein that may be involved in the presentation of the laminin-binding O-linked carbohydrate chain of alpha-dystroglycan (a-DG), which forms transmembrane linkages between the extracellular matrix and the exoskeleton. Some pathogens use this O-linked carbohydrate unit for host entry. Loss of function compound heterozygous mutations in this gene were found in a human patient affected by the Walker-Warburg syndrome (WWS) phenotype. Mice lacking this gene contain misplaced neurons (heterotopia) in some regions of the brain, possibly from defects in neuronal migration. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2013]

POMK Gene-Disease associations (from GenCC):

• muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type a, 12

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, G2P, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• congenital muscular dystrophy with cerebellar involvement

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• limb-girdle muscular dystrophy due to POMK deficiency

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• muscular dystrophy-dystroglycanopathy, type A

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.05957198).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POMK	NM_032237.5	c.1024A>C	p.Met342Leu	missense_variant	Exon 5 of 5	ENST00000331373.10	NP_115613.1
POMK	NM_001277971.2	c.1024A>C	p.Met342Leu	missense_variant	Exon 4 of 4		NP_001264900.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POMK	ENST00000331373.10	c.1024A>C	p.Met342Leu	missense_variant	Exon 5 of 5	2	NM_032237.5	ENSP00000331258.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460450 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726556

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33468

American (AMR) AF: 0.00 AC: 0 AN: 44668

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26088

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 86200

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52530

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5754

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111692

Other (OTH) AF: 0.00 AC: 0 AN: 60362

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.097
BayesDel_addAF	Benign	-0.35	T
BayesDel_noAF	Benign	-0.74
CADD	Benign	1.8
DANN	Benign	0.55
DEOGEN2	Benign	0.0016	T;T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.27	N
LIST_S2	Benign	0.37	T;.
M_CAP	Benign	0.0038	T
MetaRNN	Benign	0.060	T;T
MetaSVM	Benign	-0.96	T
MutationAssessor	Benign	0.69	N;N
PhyloP100		1.3
PrimateAI	Benign	0.27	T
PROVEAN	Benign	-0.070	.;N
REVEL	Benign	0.029
Sift	Benign	0.57	.;T
Sift4G	Benign	0.52	T;T
Polyphen		0.0	B;B
Vest4		0.050
MutPred		0.33		Loss of disorder (P = 0.0731);Loss of disorder (P = 0.0731);
MVP		0.17
MPC		0.076
ClinPred		0.0096	T
GERP RS		1.5
Varity_R		0.036
gMVP		0.25
Mutation Taster		=95/5	polymorphism

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

Other links and lift over

dbSNP: rs762404960; hg19: chr8-42977991;