rs146579299

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM1BP4_StrongBS1_Supporting

The NM_018941.4(CLN8):c.779C>T(p.Pro260Leu) variant causes a missense change. The variant allele was found at a frequency of 0.000159 in 1,614,194 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. P260P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00011 ( 0 hom. )

Consequence

CLN8
NM_018941.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:8B:3

Conservation

PhyloP100: 5.65

Publications

6 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: Likely_benign. The variant received -3 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 10 uncertain in NM_018941.4

BP4

Computational evidence support a benign effect (MetaRNN=0.017316312).

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.000657 (100/152304) while in subpopulation AFR AF = 0.00219 (91/41564). AF 95% confidence interval is 0.00183. There are 0 homozygotes in GnomAd4. There are 44 alleles in the male GnomAd4 subpopulation. Median coverage is 33. 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.779C>T	p.Pro260Leu	missense_variant	Exon 3 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.779C>T	p.Pro260Leu	missense_variant	Exon 3 of 3	1	NM_018941.4	ENSP00000328182.4		Q9UBY8
KBTBD11-OT1	ENST00000635855.1 link	n.543+8888C>T		intron_variant	Intron 2 of 29	5		ENSP00000489726.1		A0A1B0GTJ5

Frequencies

GnomAD3 genomes

AF:

0.000651

AC:

AN:

152186

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00217

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000458

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

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:

0.000227

AC:

AN:

251410

AF XY:

0.000132

show subpopulations

Gnomad AFR exome

AF:

0.00265

Gnomad AMR exome

AF:

0.000260

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000107

AC:

157

AN:

1461890

Hom.:

Cov.:

AF XY:

0.0000811

AC XY:

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.00329

AC:

110

AN:

33480

American (AMR)

AF:

0.000313

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.000101

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000812

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000540

AC:

AN:

1112012

Other (OTH)

AF:

0.000248

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.480

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:

0.000657

AC:

100

AN:

152304

Hom.:

Cov.:

AF XY:

0.000591

AC XY:

AN XY:

74478

show subpopulations

African (AFR)

AF:

0.00219

AC:

AN:

41564

American (AMR)

AF:

0.000458

AC:

AN:

15300

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5178

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68030

Other (OTH)

AF:

0.000473

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.508

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:

0.000314

Hom.:

Bravo

AF:

0.000812

ESP6500AA

AF:

0.00113

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000255

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:8Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:5

May 07, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Reported previously with a second variant in a patient with malnutrition, developmental delay, absent speech, severe intellectual disability, epilepsy, and cerebellar and cerebral atrophy (PMID: 38751748); Reported previously with a second variant in siblings with adult-onset nyctalopia (PMID: 36912596); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 36912596, 38751748, 32348865) -

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Feb 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

CLN8: PM2, PM3:Supporting -

Apr 21, 2023

Mayo Clinic Laboratories, Mayo Clinic

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

Pathogenic:1Uncertain:1

Feb 29, 2024

Bioinformatics Unit, Institut Pasteur de Montevideo

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The two variants found can be classified as likely pathogenic according to ACMG criteria: i. Pro260Leu missense variant has low frequency (PM2), detected in trans with another likely pathogenic mutation (PM3), is a missense variant in a gene where missense variants are a common mechanism of disease (PP2). Additionally, multiple lines of evidence of computational in silico scores support a deleterious effect (PP3), the patient's phenotype is highly specific for a disease with a single gene etiology (PP4). Hence, 2 PM and 3 PP, leads to a likely pathogenic classification; ii. Val261Ala missense variant can also be classified as likely pathogenic with the same rules applied. We have identified the two variants in compound heterozygosity with additional data to consider them as likely pathogenic mutations. -

Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

CLN8 NM_018941 exon 3 p.Pro260Leu (c.779C>T): This variant has not been reported in the literature but is present in 64/24030 African individuals in the Genome Aggregation Database (http://gnomad.broadinstitute.org/rs146579299). This variant is present in ClinVar (Variation ID:205196). Evolutionary conservation and computational predictive tools for this variant are unclear. In summary, data on this variant is insufficient for disease classification. Therefore, the clinical significance of this variant is uncertain -

not specified

Uncertain:1Benign:1

Aug 05, 2024

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

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: CLN8 c.779C>T (p.Pro260Leu) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00023 in 251410 control chromosomes, predominantly at a frequency of 0.0026 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 3 fold of the estimated maximal expected allele frequency for a pathogenic variant in CLN8 causing Neuronal Ceroid-Lipofuscinosis (Batten Disease) phenotype (0.00087). c.779C>T has been reported in the literature in two individuals affected with retinal dystrophy, without strong evidence for causality (Kolesnikova_2023). These report(s) do not provide unequivocal conclusions about association of the variant with Neuronal Ceroid-Lipofuscinosis (Batten Disease). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 36912596). ClinVar contains an entry for this variant (Variation ID: 205196). Based on the evidence outlined above, the variant was classified as likely benign. -

May 04, 2022

Mendelics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Neuronal ceroid lipofuscinosis 8

Uncertain:1

Jun 25, 2020

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Inborn genetic diseases

Benign:1

Feb 05, 2024

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Neuronal ceroid lipofuscinosis

Benign:1

Jan 27, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.61

BayesDel_addAF

Benign

-0.14

BayesDel_noAF

Uncertain

0.030

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.39

T;T;T;T;T

Eigen

Uncertain

0.27

Eigen_PC

Uncertain

0.24

FATHMM_MKL

Uncertain

0.96

M_CAP

Uncertain

0.16

MetaRNN

Benign

0.017

T;T;T;T;T

MetaSVM

Uncertain

0.33

MutationAssessor

Uncertain

2.5

M;M;M;M;M

PhyloP100

5.7

PrimateAI

Uncertain

0.63

PROVEAN

Uncertain

-3.0

D;.;.;.;.

REVEL

Uncertain

0.57

Sift

Pathogenic

0.0

D;.;.;.;.

Sift4G

Uncertain

0.0050

D;.;.;.;.

Polyphen

0.90

P;P;P;P;P

Vest4

0.41

MVP

0.92

MPC

0.29

ClinPred

0.13

GERP RS

4.3

Varity_R

0.36

gMVP

0.77

Mutation Taster

=35/65

disease causing

(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