rs386834125

Variant names:

• chr8-1771281-A-C
• rs386834125
• NM_018941.4:c.227A>C

Your query was ambiguous. Multiple possible variants found:

• chr8-1771281-A-C
• chr8-1771281-A-G

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PM5 PP3_Moderate

The NM_018941.4(CLN8):​c.227A>C​(p.Gln76Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,864 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Q76R) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CLN8 NM_018941.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.66
• Publications: 0 publications found

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

KBTBD11-OT1 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 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, 9 uncertain in NM_018941.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr8-1771281-A-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 56705.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.891

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CLN8	NM_018941.4	c.227A>C	p.Gln76Pro	missense_variant	Exon 2 of 3	ENST00000331222.6	NP_061764.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CLN8	ENST00000331222.6	c.227A>C	p.Gln76Pro	missense_variant	Exon 2 of 3	1	NM_018941.4	ENSP00000328182.4
KBTBD11-OT1	ENST00000635855.1	n.227A>C		non_coding_transcript_exon_variant	Exon 2 of 30	5		ENSP00000489726.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461864 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727230

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111986

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neuronal ceroid lipofuscinosis Uncertain:1

Jun 15, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt CLN8 protein function. This variant has not been reported in the literature in individuals affected with CLN8-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glutamine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 76 of the CLN8 protein (p.Gln76Pro). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.68
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.72	.;D;D;D;D;.;D;.;.
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.87	D;.;.;.;.;D;.;D;T
M_CAP	Uncertain	0.24	D
MetaRNN	Pathogenic	0.89	D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.61	D
MutationAssessor	Uncertain	2.6	.;M;M;M;M;.;M;.;.
PhyloP100		8.7
PrimateAI	Uncertain	0.73	T
PROVEAN	Benign	-1.8	.;N;.;.;.;.;.;.;.
REVEL	Pathogenic	0.84
Sift	Benign	0.062	.;T;.;.;.;.;.;.;.
Sift4G	Pathogenic	0.0	D;T;.;.;.;.;.;D;.
Polyphen		1.0	.;D;D;D;D;.;D;.;.
Vest4		0.88
MutPred		0.70		Loss of catalytic residue at Q76 (P = 0.0018);Loss of catalytic residue at Q76 (P = 0.0018);Loss of catalytic residue at Q76 (P = 0.0018);Loss of catalytic residue at Q76 (P = 0.0018);Loss of catalytic residue at Q76 (P = 0.0018);Loss of catalytic residue at Q76 (P = 0.0018);Loss of catalytic residue at Q76 (P = 0.0018);Loss of catalytic residue at Q76 (P = 0.0018);Loss of catalytic residue at Q76 (P = 0.0018);
MVP		0.95
MPC		0.30
ClinPred		0.85	D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.43
gMVP		0.91
Mutation Taster		=39/61	disease causing

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

Other links and lift over

dbSNP: rs386834125; hg19: chr8-1719447;