8-1771254-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM1BS1_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). Synonymous variant affecting the same amino acid position (i.e. A67A) has been classified as Likely benign.

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

Publications

8 publications found

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 Gene-Disease associations (from GenCC):

neuronal ceroid lipofuscinosis
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
neuronal ceroid lipofuscinosis 8
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P, Orphanet, Ambry Genetics, Myriad Women’s Health
neuronal ceroid lipofuscinosis 8 northern epilepsy variant
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
autism spectrum disorder
Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics

CLN8 links:

KBTBD11-OT1 (HGNC:):

KBTBD11-OT1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_018941.4

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 the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. 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

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
KBTBD11-OT1	ENST00000635855.1 link	n.200C>T		non_coding_transcript_exon_variant	Exon 2 of 30	5		ENSP00000489726.1

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

GnomAD2 exomes

AF:

0.0000318

AC:

AN:

251354

AF XY:

0.0000368

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 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

African (AFR)

AF:

0.0000299

AC:

AN:

33450

American (AMR)

AF:

0.000403

AC:

AN:

44700

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39674

South Asian (SAS)

AF:

0.00

AC:

AN:

86250

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53410

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000153

AC:

AN:

1111446

Other (OTH)

AF:

0.000215

AC:

AN:

60372

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000283

AC:

AN:

152110

Hom.:

Cov.:

AF XY:

0.000296

AC XY:

AN XY:

74290

show subpopulations

African (AFR)

AF:

0.000169

AC:

AN:

41412

American (AMR)

AF:

0.00229

AC:

AN:

15266

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10600

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68032

Other (OTH)

AF:

0.000478

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.491

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

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

Aug 13, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Reported 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 (PMID: 29503925); In silico analysis suggests that this missense variant does not alter protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 29503925, 34532411) -

Oct 28, 2014

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

(source)

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;.;.

PhyloP100

5.6

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

Mutation Taster

=23/77

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over