8-24955548-C-T

Variant names:

• chr8-24955548-C-T
• rs864622499
• NM_006158.5:c.968G>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1 PM5 PP2 BP4

The NM_006158.5(NEFL):​c.968G>A​(p.Arg323Gln) variant causes a missense change. The variant allele was found at a frequency of 0.00000372 in 1,613,472 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign 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. R323P) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: NEFL NM_006158.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.75
• Publications: 0 publications found

Genes affected

NEFL (HGNC:7739): (neurofilament light chain) Neurofilaments are type IV intermediate filament heteropolymers composed of light, medium, and heavy chains. Neurofilaments comprise the axoskeleton and they functionally maintain the neuronal caliber. They may also play a role in intracellular transport to axons and dendrites. This gene encodes the light chain neurofilament protein. Mutations in this gene cause Charcot-Marie-Tooth disease types 1F (CMT1F) and 2E (CMT2E), disorders of the peripheral nervous system that are characterized by distinct neuropathies. A pseudogene has been identified on chromosome Y. [provided by RefSeq, Oct 2008]

NEFL Gene-Disease associations (from GenCC):

• Charcot-Marie-Tooth disease

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• Charcot-Marie-Tooth disease type 2

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Charcot-Marie-Tooth disease type 1F

  Inheritance: AR, AD Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
• Charcot-Marie-Tooth disease type 2E

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Charcot-Marie-Tooth disease type 2B5

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ENSG00000272157 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a region_of_interest Coil 2B (size 115) in uniprot entity NFL_HUMAN there are 9 pathogenic changes around while only 1 benign (90%) in NM_006158.5
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr8-24955548-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 220372.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 19 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Trascript score misZ: 0.63774 (below the threshold of 3.09). GenCC associations: The gene is linked to Charcot-Marie-Tooth disease type 2B5, Charcot-Marie-Tooth disease type 2, Charcot-Marie-Tooth disease type 2E, Charcot-Marie-Tooth disease, Charcot-Marie-Tooth disease type 1F.
• BP4: Computational evidence support a benign effect (MetaRNN=0.35600418).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NEFL	NM_006158.5	c.968G>A	p.Arg323Gln	missense_variant	Exon 1 of 4	ENST00000610854.2	NP_006149.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NEFL	ENST00000610854.2	c.968G>A	p.Arg323Gln	missense_variant	Exon 1 of 4	1	NM_006158.5	ENSP00000482169.2
NEFL	ENST00000615973.1	n.1174G>A		non_coding_transcript_exon_variant	Exon 1 of 1	6
ENSG00000272157	ENST00000607735.3	n.-143C>T		upstream_gene_variant		6

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152066 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000402 AC: 1 AN: 249046 AF XY: 0.00000740

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000885

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461406 Hom.: 0 Cov.: 37 AF XY: 0.00000275 AC XY: 2 AN XY: 726982

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: 53102

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

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111866

Other (OTH) AF: 0.00 AC: 0 AN: 60372

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152066 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74272

African (AFR) AF: 0.00 AC: 0 AN: 41394

American (AMR) AF: 0.00 AC: 0 AN: 15278

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5168

South Asian (SAS) AF: 0.00 AC: 0 AN: 4818

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10594

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000441 AC: 3 AN: 68026

Other (OTH) AF: 0.00 AC: 0 AN: 2088

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease type 2E Uncertain:1

Oct 04, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 323 of the NEFL protein (p.Arg323Gln). This variant is present in population databases (no rsID available, gnomAD 0.002%). This variant has not been reported in the literature in individuals affected with NEFL-related conditions. 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 not expected to disrupt NEFL protein function. This variant disrupts the p.Arg323 amino acid residue in NEFL. Other variant(s) that disrupt this residue have been determined to be pathogenic (Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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	Benign	0.25
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	-0.010
CADD	Pathogenic	34
DANN	Benign	0.97
DEOGEN2	Pathogenic	0.83	D;.;T
FATHMM_MKL	Uncertain	0.81	D
LIST_S2	Uncertain	0.90	D;D;D
MetaRNN	Benign	0.36	T;T;T
PhyloP100		3.8
PrimateAI	Uncertain	0.49	T
Sift4G	Benign	0.079	T;.;T
Polyphen		0.98	D;.;.
Vest4		0.65
MVP		0.72
GERP RS		5.1
Varity_R		0.36
gMVP		0.81

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: rs864622499; hg19: chr8-24813062;