15-68208397-C-T
Variant summary
Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1PM2PP3_ModeratePP5
The NM_017882.3(CLN6):c.679G>A(p.Glu227Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000992 in 1,612,754 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. E227E) has been classified as Likely benign.
Frequency
Consequence
NM_017882.3 missense
Scores
Clinical Significance
Conservation
Publications
- ceroid lipofuscinosis, neuronal, 6AInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P, Myriad Women’s Health, Orphanet
- ceroid lipofuscinosis, neuronal, 6B (Kufs type)Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, G2P, Orphanet
- neuronal ceroid lipofuscinosisInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
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ACMG classification
Our verdict: Likely_pathogenic. The variant received 7 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152168Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000120 AC: 3AN: 249450 AF XY: 0.00000739 show subpopulations
GnomAD4 exome AF: 0.0000103 AC: 15AN: 1460586Hom.: 0 Cov.: 38 AF XY: 0.0000151 AC XY: 11AN XY: 726582 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152168Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74330 show subpopulations ⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
Age Distribution
ClinVar
Submissions by phenotype
Ceroid lipofuscinosis, neuronal, 6A Pathogenic:2Uncertain:1
The homozygous p.Glu227Lys variant in CLN6 was identified by our study in one individual with Neuronal Ceroid Lipofuscinosis. This variant has been identified in the literature in the case of one affected homozygous 19-year old male (Lynch et al. 2016, PMID: 26374131). This variant has been identified in <0.01% (1/15038) of African chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs746753722). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. In summary, the clinical significance of the p.Pro441Leu variant is uncertain. -
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A Homozygous missense variation in exon 7 of the CLN6 gene that results in the amino acid substitution of Lysine for Glutamic acid at codon 227 was detected. The observed variant c.679G>A (p.Glu227Lys) has not been reported in the 1000 genomes and has a MAF of 0.0012% in the gnomAD databases. The in silico prediction of the variant are possibly damaging by SIFT, LRT and MutationTaster2. The reference codon is conserved across species. In summary, the variant meets our criteria to be classified as likely pathogenic. -
Ceroid lipofuscinosis, neuronal, 6A;C5561927:Ceroid lipofuscinosis, neuronal, 6B (Kufs type) Pathogenic:1
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Neuronal ceroid lipofuscinosis Uncertain:1
This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 227 of the CLN6 protein (p.Glu227Lys). This variant is present in population databases (rs746753722, gnomAD 0.007%). This missense change has been observed in individual(s) with clinical features of CLN6-related conditions (PMID: 31319225, 34849271; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 522701). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt CLN6 protein function with a negative predictive value of 80%. 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:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at