chr8-24955908-G-A

Variant names:

• chr8-24955908-G-A
• rs753319598
• NM_006158.5:c.608C>T

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_006158.5(NEFL):​c.608C>T​(p.Ala203Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000138 in 1,452,744 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. A203A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: NEFL NM_006158.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.94
• Publications: 1 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 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006158.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NEFL	NM_006158.5	MANE Select	c.608C>T	p.Ala203Val	missense	Exon 1 of 4	NP_006149.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NEFL	ENST00000610854.2	TSL:1 MANE Select	c.608C>T	p.Ala203Val	missense	Exon 1 of 4	ENSP00000482169.2
	ENSG00000272157	ENST00000607735.3	TSL:6	n.218G>A		non_coding_transcript_exon	Exon 1 of 1
	NEFL	ENST00000615973.1	TSL:6	n.814C>T		non_coding_transcript_exon	Exon 1 of 1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000420 AC: 1 AN: 237834 AF XY: 0.00000765

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: 0.00000917

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000138 AC: 2 AN: 1452744 Hom.: 0 Cov.: 36 AF XY: 0.00000138 AC XY: 1 AN XY: 723232

African (AFR) AF: 0.00 AC: 0 AN: 33470

American (AMR) AF: 0.00 AC: 0 AN: 44698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26112

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 44790

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111688

Other (OTH) AF: 0.00 AC: 0 AN: 60282

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ExAC AF: 0.00000829 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Mar 24, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine with valine at codon 203 of the NEFL protein (p.Ala203Val). The alanine residue is highlyconserved and there is a small physicochemical difference between alanine and valine. 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with NEFL-related disease. This variant is present in population databases (rs753319598, ExAC 0.002%).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.57
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.23
CADD	Pathogenic	34
DANN	Benign	0.97
DEOGEN2	Uncertain	0.75	D
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.89	D
MetaRNN	Uncertain	0.52	D
PhyloP100		7.9
PrimateAI	Uncertain	0.55	T
Sift4G	Benign	0.085	T
Polyphen		0.88	P
Vest4		0.40
MVP		0.73
GERP RS		5.7
Varity_R		0.46
gMVP		0.39

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: rs753319598; hg19: chr8-24813422;