8-1771107-A-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM1

The NM_018941.4(CLN8):c.53A>T(p.Tyr18Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00019 in 1,613,922 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y18C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00020 ( 0 hom. )

Consequence

CLN8
NM_018941.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 4.42

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 2 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, 17 uncertain in NM_018941.4

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CLN8	NM_018941.4 link	c.53A>T	p.Tyr18Phe	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.53A>T	p.Tyr18Phe	missense_variant	Exon 2 of 3	1	NM_018941.4	ENSP00000328182.4		Q9UBY8
KBTBD11-OT1	ENST00000635855.1 link	n.53A>T		non_coding_transcript_exon_variant	Exon 2 of 30	5		ENSP00000489726.1		A0A1B0GTJ5

Frequencies

GnomAD3 genomes

AF:

0.000132

AC:

AN:

151910

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000656

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:

0.000265

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000195

AC:

AN:

251492

AF XY:

0.000169

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.000298

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000396

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000196

AC:

286

AN:

1461894

Hom.:

Cov.:

AF XY:

0.000172

AC XY:

125

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.000115

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000562

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000245

AC:

272

AN:

1112012

Other (OTH)

AF:

0.000132

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.485

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:

0.000132

AC:

AN:

152028

Hom.:

Cov.:

AF XY:

0.000135

AC XY:

AN XY:

74318

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41494

American (AMR)

AF:

0.0000655

AC:

AN:

15260

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5130

South Asian (SAS)

AF:

0.00

AC:

AN:

4812

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10560

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000265

AC:

AN:

67984

Other (OTH)

AF:

0.00

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.490

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:

0.000180

Hom.:

Bravo

AF:

0.000140

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.000255

AC:

EpiCase

AF:

0.000218

EpiControl

AF:

0.000178

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Mar 08, 2018

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Oct 31, 2024

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis indicates that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Inborn genetic diseases

Uncertain:1

Jan 16, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.53A>T (p.Y18F) alteration is located in exon 2 (coding exon 1) of the CLN8 gene. This alteration results from a A to T substitution at nucleotide position 53, causing the tyrosine (Y) at amino acid position 18 to be replaced by a phenylalanine (F). The in silico prediction for this alteration is inconclusive. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Neuronal ceroid lipofuscinosis 8

Uncertain:1

Jan 15, 2020

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Neuronal ceroid lipofuscinosis

Uncertain:1

Aug 20, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces tyrosine, which is neutral and polar, with phenylalanine, which is neutral and non-polar, at codon 18 of the CLN8 protein (p.Tyr18Phe). This variant is present in population databases (rs142104002, gnomAD 0.03%). This variant has not been reported in the literature in individuals affected with CLN8-related conditions. ClinVar contains an entry for this variant (Variation ID: 205202). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). 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. -

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

Uncertain:1

Dec 16, 2021

Fulgent Genetics, Fulgent Genetics

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

Benign

0.16

BayesDel_addAF

Uncertain

0.015

BayesDel_noAF

Uncertain

0.10

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.64

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

Eigen

Uncertain

0.33

Eigen_PC

Uncertain

0.27

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.79

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

M_CAP

Uncertain

0.25

MetaRNN

Uncertain

0.47

T;T;T;T;T;T;T;T;T

MetaSVM

Uncertain

0.76

MutationAssessor

Uncertain

2.6

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

PhyloP100

4.4

PrimateAI

Benign

0.47

PROVEAN

Benign

-2.1

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

REVEL

Uncertain

0.64

Sift

Pathogenic

0.0

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

Sift4G

Pathogenic

0.0

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

Polyphen

0.99

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

Vest4

0.39

MVP

0.97

MPC

0.039

ClinPred

0.32

GERP RS

4.0

Varity_R

0.29

gMVP

0.61

Mutation Taster

=75/25

polymorphism

(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