rs386834138

Positions:

• chr8-1780472-C-G
• chr8-1780472-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PP3_Moderate PP5

The NM_018941.4(CLN8):​c.766C>G​(p.Gln256Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 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 Likely pathogenic (no stars).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CLN8 NM_018941.4 missense
• Clinical Significance: Likely pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 7.37

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 Likely_pathogenic. Variant got 7 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 6 uncertain in NM_018941.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.936
• PP5: Variant 8-1780472-C-G is Pathogenic according to our data. Variant chr8-1780472-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 56719.Status of the report is no_assertion_criteria_provided, 0 stars. Variant chr8-1780472-C-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CLN8	NM_018941.4	c.766C>G	p.Gln256Glu	missense_variant	3/3	ENST00000331222.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CLN8	ENST00000331222.6	c.766C>G	p.Gln256Glu	missense_variant	3/3	1	NM_018941.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461892 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727248

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Neuronal ceroid lipofuscinosis 8 Pathogenic:1

Likely pathogenic, no assertion criteria provided

literature only

Juha Muilu Group; Institute for Molecular Medicine Finland (FIMM)

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.65
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Benign	0.32	T;T;T;T;T
Eigen	Pathogenic	0.72
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.98	D
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.94	D;D;D;D;D
MetaSVM	Pathogenic	0.85	D
MutationAssessor	Uncertain	2.5	M;M;M;M;M
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-1.3	N;.;.;.;.
REVEL	Pathogenic	0.85
Sift	Pathogenic	0.0	D;.;.;.;.
Sift4G	Uncertain	0.026	D;.;.;.;.
Polyphen		1.0	D;D;D;D;D
Vest4		0.86
MutPred		0.82		Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);Gain of loop (P = 0.0435);
MVP		0.97
MPC		0.28
ClinPred		0.97	D
GERP RS		5.2
Varity_R		0.52
gMVP		0.78

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: rs386834138; hg19: chr8-1728638;