8-1780485-C-T

Variant names:

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 4P and 5B. PM1PM2BP4_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).

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

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 Likely_benign. Variant got -1 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;

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 male gnomad4 subpopulation. Median coverage is 33. 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.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

GnomAD3 exomes

AF:

0.000227

AC:

AN:

251410

Hom.:

AF XY:

0.000132

AC XY:

AN XY:

135878

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 SAS exome

AF:

0.0000653

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

Gnomad4 AFR exome

AF:

0.00329

Gnomad4 AMR exome

AF:

0.000313

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000101

Gnomad4 SAS exome

AF:

0.0000812

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000540

Gnomad4 OTH exome

AF:

0.000248

GnomAD4 genome

AF:

0.000657

AC:

100

AN:

152304

Hom.:

Cov.:

AF XY:

0.000591

AC XY:

AN XY:

74478

show subpopulations

Gnomad4 AFR

AF:

0.00219

Gnomad4 AMR

AF:

0.000458

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000473

Alfa

AF:

0.000122

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

Uncertain significance, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, Amsterdam University Medical Center	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Feb 01, 2025	CLN8: PM2, PM3:Supporting -
Uncertain significance, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Apr 21, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Aug 07, 2024	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) -

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

Pathogenic:1Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago	Nov 11, 2021	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. -
Likely pathogenic, flagged submission	clinical testing	Bioinformatics Unit, Institut Pasteur de Montevideo	Feb 29, 2024	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. -

not specified

Uncertain:1Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Mendelics	May 04, 2022	- -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 05, 2024	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. -

Neuronal ceroid lipofuscinosis 8

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Jun 25, 2020

- -

Inborn genetic diseases

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 05, 2024

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

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 27, 2025

- -

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

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

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

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