8-1771254-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1PM2BS1_Supporting

The NM_018941.4(CLN8):c.200C>T(p.Ala67Val) variant causes a missense change. The variant allele was found at a frequency of 0.0000576 in 1,613,312 control chromosomes in the GnomAD database, including 1 homozygotes. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00028 ( 1 hom., cov: 32)

Exomes 𝑓: 0.000034 ( 0 hom. )

Consequence

CLN8
NM_018941.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:7

Conservation

PhyloP100: 5.60

Variant links:

Genes affected

CLN8 (HGNC:2079): (CLN8 transmembrane ER and ERGIC protein) This gene encodes a transmembrane protein belonging to a family of proteins containing TLC domains, which are postulated to function in lipid synthesis, transport, or sensing. The protein localizes to the endoplasmic reticulum (ER), and may recycle between the ER and ER-Golgi intermediate compartment. Mutations in this gene are associated with a disorder characterized by progressive epilepsy with cognitive disabilities (EPMR), which is a subtype of neuronal ceroid lipofuscinoses (NCL). Patients with mutations in this gene have altered levels of sphingolipid and phospholipids in the brain. [provided by RefSeq, Jul 2017]

CLN8 links:

KBTBD11-OT1 (HGNC:):

KBTBD11-OT1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PM1

In a domain TLC (size 200) in uniprot entity CLN8_HUMAN there are 17 pathogenic changes around while only 5 benign (77%) in NM_018941.4

PM2

Very rare variant in population databases, with high coverage;

BS1

Variant frequency is greater than expected in population amr. gnomad4 allele frequency = 0.000283 (43/152110) while in subpopulation AMR AF= 0.00229 (35/15266). AF 95% confidence interval is 0.00169. There are 1 homozygotes in gnomad4. There are 22 alleles in male gnomad4 subpopulation. Median coverage is 32. 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
CLN8	NM_018941.4 link	c.200C>T	p.Ala67Val	missense_variant	Exon 2 of 3	ENST00000331222.6	NP_061764.2	Q9UBY8A0A024QZ57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CLN8	ENST00000331222.6 link	c.200C>T	p.Ala67Val	missense_variant	Exon 2 of 3	1	NM_018941.4	ENSP00000328182.4		Q9UBY8
KBTBD11-OT1	ENST00000635855.1 link	n.200C>T		non_coding_transcript_exon_variant	Exon 2 of 30	5		ENSP00000489726.1		A0A1B0GTJ5

Frequencies

GnomAD3 genomes

AF:

0.000283

AC:

AN:

152110

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000169

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00229

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:

0.000478

GnomAD3 exomes

AF:

0.0000318

AC:

AN:

251354

Hom.:

AF XY:

0.0000368

AC XY:

AN XY:

135864

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.000489

GnomAD4 exome

AF:

0.0000342

AC:

AN:

1461202

Hom.:

Cov.:

AF XY:

0.0000316

AC XY:

AN XY:

726760

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.000403

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000153

Gnomad4 OTH exome

AF:

0.000215

GnomAD4 genome

AF:

0.000283

AC:

AN:

152110

Hom.:

Cov.:

AF XY:

0.000296

AC XY:

AN XY:

74290

show subpopulations

Gnomad4 AFR

AF:

0.000169

Gnomad4 AMR

AF:

0.00229

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:

0.000478

Bravo

AF:

0.000552

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000330

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:7

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Oct 28, 2014

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jun 23, 2021

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Reported previously in a sibling pair with seizures and vision loss who were compound heterozygous for A67V and a pathogenic CLN8 copy number variant; however, no additional information was provided to unequivocally demonstrate that the A67V variant is pathogenic and functional studies were not performed (Sanchez et al., 2016); Not observed at significant frequency in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 29503925, 27535533, 21990111, 23274885) -

Neuronal ceroid lipofuscinosis

Pathogenic:1

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 67 of the CLN8 protein (p.Ala67Val). This variant is present in population databases (rs373957283, gnomAD 0.01%). This missense change has been observed in individual(s) with neuronal ceroid lipofuscinosis (PMID: 29503925). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 195345). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed for this missense variant. However, the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on CLN8 protein function. For these reasons, this variant has been classified as Pathogenic. -

not specified

Uncertain:1

Sep 09, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: CLN8 c.200C>T (p.Ala67Val) results in a non-conservative amino acid change located in the TRAM/LAG1/CLN8 homology domain (IPR006634) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 3.2e-05 in 251354 control chromosomes. c.200C>T has been reported in the literature in compound heterozygous individuals affected with Neuronal Ceroid-Lipofuscinosis (Batten Disease) (e.g. Sanchez_2018). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. ClinVar contains an entry for this variant (Variation ID: 195345). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Inborn genetic diseases

Uncertain:1

Dec 02, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.200C>T (p.A67V) alteration is located in exon 2 (coding exon 1) of the CLN8 gene. This alteration results from a C to T substitution at nucleotide position 200, causing the alanine (A) at amino acid position 67 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Neuronal ceroid lipofuscinosis 1

Uncertain:1

Apr 21, 2023

Mendelics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Neuronal ceroid lipofuscinosis 8

Uncertain:1

Sep 16, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Neuronal ceroid lipofuscinosis 8;C1864923:Neuronal ceroid lipofuscinosis 8 northern epilepsy variant

Uncertain:1

Jul 07, 2021

New York Genome Center

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.72

BayesDel_addAF

Pathogenic

0.23

BayesDel_noAF

Pathogenic

0.33

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.46

.;T;T;T;T;.;T;.;.

Eigen

Uncertain

0.64

Eigen_PC

Uncertain

0.60

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.93

D;.;.;.;.;D;.;D;D

M_CAP

Uncertain

0.23

MetaRNN

Uncertain

0.50

D;D;D;D;D;D;D;D;D

MetaSVM

Uncertain

0.43

MutationAssessor

Uncertain

2.6

.;M;M;M;M;.;M;.;.

PrimateAI

Uncertain

0.66

PROVEAN

Benign

-1.9

.;N;.;.;.;.;.;.;.

REVEL

Pathogenic

0.76

Sift

Uncertain

0.0040

.;D;.;.;.;.;.;.;.

Sift4G

Pathogenic

0.0

D;D;.;.;.;.;.;D;.

Polyphen

1.0

.;D;D;D;D;.;D;.;.

Vest4

0.72

MVP

0.93

MPC

0.28

ClinPred

0.42

GERP RS

5.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.32

gMVP

0.67

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