rs1388505858

Variant names:

• chr6-18121594-G-A
• rs1388505858
• NM_198586.3:c.1013C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2 PP2 BP4

The NM_198586.3(NHLRC1):​c.1013C>T​(p.Thr338Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,230 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: NHLRC1 NM_198586.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.32
• 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 2 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.37309456).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NHLRC1	NM_198586.3	c.1013C>T	p.Thr338Ile	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.1013C>T	p.Thr338Ile	missense_variant	Exon 1 of 1	6	NM_198586.3	ENSP00000345464.3

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152230 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152230 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74370

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

African (AFR) AF: 0.0000241 AC: 1 AN: 41454

American (AMR) AF: 0.00 AC: 0 AN: 15290

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10630

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68040

Other (OTH) AF: 0.00 AC: 0 AN: 2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Lafora disease Uncertain:1

Aug 15, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals affected with NHLRC1-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.01%). This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 338 of the NHLRC1 protein (p.Thr338Ile). ClinVar contains an entry for this variant (Variation ID: 462937). 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Uncertain	0.063	T
BayesDel_noAF	Benign	-0.15
CADD	Benign	16
DANN	Uncertain	0.99
DEOGEN2	Benign	0.20	T
Eigen	Benign	-0.21
Eigen_PC	Benign	-0.17
FATHMM_MKL	Benign	0.45	N
LIST_S2	Benign	0.59	T
M_CAP	Benign	0.034	D
MetaRNN	Benign	0.37	T
MetaSVM	Benign	-0.61	T
MutationAssessor	Uncertain	2.4	M
PhyloP100		1.3
PrimateAI	Benign	0.36	T
PROVEAN	Uncertain	-2.4	N
REVEL	Benign	0.26
Sift	Benign	0.068	T
Sift4G	Uncertain	0.060	T
Polyphen		0.48	P
Vest4		0.47
MutPred		0.37		Loss of glycosylation at T338 (P = 0.0698);
MVP		0.92
MPC		0.47
ClinPred		0.51	D
GERP RS		4.9
Varity_R		0.081
gMVP		0.43
Mutation Taster		=87/13	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs1388505858; hg19: chr6-18121825;