chr6-18121894-G-T

Variant names:

• chr6-18121894-G-T
• rs747276703
• NM_198586.3:c.713C>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_198586.3(NHLRC1):​c.713C>A​(p.Ser238Tyr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S238C) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NHLRC1 NM_198586.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.77
• Publications: 0 publications found

Genes affected

NHLRC1 (HGNC:21576): (NHL repeat containing E3 ubiquitin protein ligase 1) The protein encoded by this gene is a single subunit E3 ubiquitin ligase. Laforin is polyubiquitinated by the encoded protein. Defects in this intronless gene lead to an accumulation of laforin and onset of Lafora disease, also known as progressive myoclonic epilepsy type 2 (EPM2).[provided by RefSeq, Mar 2010]

NHLRC1 Gene-Disease associations (from GenCC):

• Lafora disease

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 13 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 0.49521 (below the threshold of 3.09). Trascript score misZ: -0.085446 (below the threshold of 3.09). GenCC associations: The gene is linked to Lafora disease.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NHLRC1	NM_198586.3	c.713C>A	p.Ser238Tyr	missense_variant	Exon 1 of 1	ENST00000340650.6	NP_940988.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NHLRC1	ENST00000340650.6	c.713C>A	p.Ser238Tyr	missense_variant	Exon 1 of 1	6	NM_198586.3	ENSP00000345464.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Lafora disease Uncertain:1

Dec 06, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces serine, which is neutral and polar, with tyrosine, which is neutral and polar, at codon 238 of the NHLRC1 protein (p.Ser238Tyr). 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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt NHLRC1 protein function. ClinVar contains an entry for this variant (Variation ID: 860322). This variant has not been reported in the literature in individuals affected with NHLRC1-related conditions. This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.19
BayesDel_addAF	Uncertain	0.058	T
BayesDel_noAF	Benign	-0.15
CADD	Uncertain	23
DANN	Uncertain	0.99
DEOGEN2	Benign	0.18	T
Eigen	Benign	0.091
Eigen_PC	Benign	0.076
FATHMM_MKL	Benign	0.46	N
LIST_S2	Benign	0.78	T
M_CAP	Benign	0.057	D
MetaRNN	Uncertain	0.46	T
MetaSVM	Uncertain	-0.14	T
MutationAssessor	Benign	1.2	L
PhyloP100		2.8
PrimateAI	Benign	0.42	T
PROVEAN	Uncertain	-2.5	N
REVEL	Uncertain	0.36
Sift	Uncertain	0.025	D
Sift4G	Uncertain	0.0090	D
Polyphen		0.92	P
Vest4		0.32
MutPred		0.41		Loss of disorder (P = 0.178);
MVP		0.90
MPC		0.78
ClinPred		0.82	D
GERP RS		5.2
Varity_R		0.17
gMVP		0.76
Mutation Taster		=69/31	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs747276703; hg19: chr6-18122125;