8-24956494-G-T

Variant names:

• chr8-24956494-G-T
• rs886043551
• NM_006158.5:c.22C>A

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 8P and 1B. PM1 PM2 PM5 PP2 PP5 BP4

The NM_006158.5(NEFL):​c.22C>A​(p.Pro8Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P8R) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: NEFL NM_006158.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 2.60
• Publications: 3 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: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a region_of_interest Head (size 90) in uniprot entity NFL_HUMAN there are 10 pathogenic changes around while only 3 benign (77%) in NM_006158.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr8-24956493-GG-CT is described in ClinVar as Pathogenic. ClinVar VariationId is 14030.Status of the report is no_assertion_criteria_provided, 0 stars.
• 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.
• PP5: Variant 8-24956494-G-T is Pathogenic according to our data. Variant chr8-24956494-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 287020.
• BP4: Computational evidence support a benign effect (MetaRNN=0.334376). . Strength limited to SUPPORTING due to the PP5.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NEFL	NM_006158.5	c.22C>A	p.Pro8Thr	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.22C>A	p.Pro8Thr	missense_variant	Exon 1 of 4	1	NM_006158.5	ENSP00000482169.2
ENSG00000272157	ENST00000607735.3	n.804G>T		non_coding_transcript_exon_variant	Exon 1 of 1	6
NEFL	ENST00000615973.1	n.228C>A		non_coding_transcript_exon_variant	Exon 1 of 1	6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1447044 Hom.: 0 Cov.: 36 AF XY: 0.00 AC XY: 0 AN XY: 718418

African (AFR) AF: 0.00 AC: 0 AN: 33218

American (AMR) AF: 0.00 AC: 0 AN: 42280

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25730

East Asian (EAS) AF: 0.00 AC: 0 AN: 39064

South Asian (SAS) AF: 0.00 AC: 0 AN: 83632

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51832

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5296

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1106194

Other (OTH) AF: 0.00 AC: 0 AN: 59798

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

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

May 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces proline, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 8 of the NEFL protein (p.Pro8Thr). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of Charcot-Marie-Tooth disease (Invitae). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 287020). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on NEFL protein function. This variant disrupts the p.Pro8 amino acid residue in NEFL. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11220745, 12566280, 17620486, 22155564, 23618875, 28501821). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Charcot-Marie-Tooth disease Uncertain:1

-

Inherited Neuropathy Consortium

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: literature only

- -

not provided Uncertain:1

Apr 12, 2016

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.20
BayesDel_addAF	Uncertain	0.096	D
BayesDel_noAF	Benign	-0.10
CADD	Pathogenic	27
DANN	Benign	0.97
DEOGEN2	Uncertain	0.48	T;.;T
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Benign	0.77	T;T;T
MetaRNN	Benign	0.33	T;T;T
PhyloP100		2.6
PrimateAI	Uncertain	0.62	T
Sift4G	Benign	0.57	T;.;T
Polyphen		1.0	D;.;.
Vest4		0.23
MVP		0.85
GERP RS		5.6
PromoterAI		0.035	Neutral
Varity_R		0.37
gMVP		0.80

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: rs886043551; hg19: chr8-24814008;