rs1554451522

Positions:

• chr8-1780336-C-G
• chr8-1780336-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The ENST00000331222.6(CLN8):​c.630C>G​(p.His210Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000821 in 1,461,892 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. H210H) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: CLN8 ENST00000331222.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 2.91

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 9 uncertain in ENST00000331222.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.798

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CLN8	NM_018941.4	c.630C>G	p.His210Gln	missense_variant	3/3	ENST00000331222.6	NP_061764.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CLN8	ENST00000331222.6	c.630C>G	p.His210Gln	missense_variant	3/3	1	NM_018941.4	ENSP00000328182	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461892 Hom.: 0 Cov.: 32 AF XY: 0.00000825 AC XY: 6 AN XY: 727246

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000302

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

not provided

Breakthrough Genomics, Breakthrough Genomics

-

- -

Neuronal ceroid lipofuscinosis Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 15, 2022

This sequence change replaces histidine, which is basic and polar, with glutamine, which is neutral and polar, at codon 210 of the CLN8 protein (p.His210Gln). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CLN8-related conditions. 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: "Probably Damaging"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.69
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.71	D;D;D;D;D
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.45
FATHMM_MKL	Uncertain	0.94	D
M_CAP	Uncertain	0.10	D
MetaRNN	Pathogenic	0.80	D;D;D;D;D
MetaSVM	Uncertain	0.29	D
MutationAssessor	Uncertain	2.4	M;M;M;M;M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-1.7	N;.;.;.;.
REVEL	Pathogenic	0.65
Sift	Uncertain	0.015	D;.;.;.;.
Sift4G	Benign	0.083	T;.;.;.;.
Polyphen		1.0	D;D;D;D;D
Vest4		0.47
MutPred		0.59		Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);Gain of helix (P = 0.0425);
MVP		0.92
MPC		0.28
ClinPred		0.92	D
GERP RS		3.4
Varity_R		0.21
gMVP		0.65

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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

Other links and lift over

dbSNP: rs1554451522; hg19: chr8-1728502;