chr8-1770928-T-C

Position:

• chr8-1770928-T-C

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_018941.4(CLN8):​c.-123-4T>C variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00132 in 827,392 control chromosomes in the GnomAD database, including 10 homozygotes. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0046 (3 hom., cov: 32)
  • Exomes 𝑓: 0.00058 (7 hom.)
• Consequence: CLN8 NM_018941.4 splice_region, splice_polypyrimidine_tract, intron
• Scores: Splicing: ADA: 0.00008189
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:5
• Conservation: PhyloP100: -0.605

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 Benign. Variant got -20 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.86).
• BP6: Variant 8-1770928-T-C is Benign according to our data. Variant chr8-1770928-T-C is described in ClinVar as [Likely_benign]. Clinvar id is 136805.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr8-1770928-T-C is described in Lovd as [Likely_benign]. Variant chr8-1770928-T-C is described in Lovd as [Benign].
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0046 (701/152276) while in subpopulation AFR AF= 0.0159 (660/41550). AF 95% confidence interval is 0.0149. There are 3 homozygotes in gnomad4. There are 325 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 3 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CLN8	NM_018941.4	c.-123-4T>C		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000331222.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CLN8	ENST00000331222.6	c.-123-4T>C		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		1	NM_018941.4	P1

Frequencies

GnomAD3 genomes AF: 0.00460 AC: 700 AN: 152158 Hom.: 3 Cov.: 32

Gnomad AFR AF: 0.0159

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00190

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000414

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00431

GnomAD4 exome AF: 0.000581 AC: 392 AN: 675116 Hom.: 7 Cov.: 9 AF XY: 0.000408 AC XY: 145 AN XY: 355154

Gnomad4 AFR exome AF: 0.0178

Gnomad4 AMR exome AF: 0.000763

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000612

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000163

Gnomad4 OTH exome AF: 0.000904

GnomAD4 genome AF: 0.00460 AC: 701 AN: 152276 Hom.: 3 Cov.: 32 AF XY: 0.00437 AC XY: 325 AN XY: 74454

Gnomad4 AFR AF: 0.0159

Gnomad4 AMR AF: 0.00190

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00426

Alfa AF: 0.00245 Hom.: 1

Bravo AF: 0.00516

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:2

Benign, criteria provided, single submitter	clinical testing	GeneDx	Sep 05, 2013	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

not provided Benign:2

Benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -
Likely benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -

Neuronal ceroid lipofuscinosis 8;C1864923:Neuronal ceroid lipofuscinosis 8 northern epilepsy variant Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Sep 13, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.86
CADD	Benign	0.76
DANN	Benign	0.44

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000082
dbscSNV1_RF	Benign	0.0040
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

Other links and lift over

dbSNP: rs114189810; hg19: chr8-1719094;