chr17-31249021-A-C

Position:

• chr17-31249021-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The NM_001042492.3(NF1):​c.4012A>C​(p.Asn1338His) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,840 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.84

Genes affected

NF1 (HGNC:7765): (neurofibromin 1) This gene product appears to function as a negative regulator of the ras signal transduction pathway. Mutations in this gene have been linked to neurofibromatosis type 1, juvenile myelomonocytic leukemia and Watson syndrome. The mRNA for this gene is subject to RNA editing (CGA>UGA->Arg1306Term) resulting in premature translation termination. Alternatively spliced transcript variants encoding different isoforms have also been described for this gene. [provided by RefSeq, Jul 2008]

NF1 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a domain Ras-GAP (size 216) in uniprot entity NF1_HUMAN there are 42 pathogenic changes around while only 3 benign (93%) in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), NF1. . Gene score misZ 6.5427 (greater than the threshold 3.09). Trascript score misZ 8.4054 (greater than threshold 3.09). GenCC has associacion of gene with neurofibromatosis, familial spinal, hereditary pheochromocytoma-paraganglioma, neurofibromatosis type 1, Watson syndrome, neurofibromatosis-Noonan syndrome, Moyamoya disease, familial ovarian cancer.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NF1	NM_001042492.3	c.4012A>C	p.Asn1338His	missense_variant	30/58	ENST00000358273.9	NP_001035957.1
NF1	NM_000267.3	c.4012A>C	p.Asn1338His	missense_variant	30/57		NP_000258.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NF1	ENST00000358273.9	c.4012A>C	p.Asn1338His	missense_variant	30/58	1	NM_001042492.3	ENSP00000351015.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461840 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727226

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 15, 2017

This sequence change replaces asparagine with histidine at codon 1338 of the NF1 protein (p.Asn1338His). The asparagine residue is moderately conserved and there is a small physicochemical difference between asparagine and histidine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a NF1-related disease. ClinVar contains an entry for this variant (Variation ID: 219670). Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). In summary, this variant is a rare missense change with uncertain impact on protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.070
BayesDel_addAF	Uncertain	0.056	T
BayesDel_noAF	Benign	-0.16
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	D;.;D
Eigen	Uncertain	0.48
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Benign	0.75	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Pathogenic	0.40	D
MetaRNN	Uncertain	0.74	D;D;D
MetaSVM	Uncertain	0.26	D
MutationAssessor	Benign	1.3	L;L;.
PrimateAI	Uncertain	0.62	T
PROVEAN	Uncertain	-3.6	D;D;D
REVEL	Uncertain	0.57
Sift	Benign	0.12	T;T;T
Sift4G	Uncertain	0.0020	D;D;D
Polyphen		0.56	P;B;.
Vest4		0.58
MutPred		0.55		Gain of disorder (P = 0.1419);Gain of disorder (P = 0.1419);.;
MVP		0.81
MPC		1.0
ClinPred		0.97	D
GERP RS		5.7
Varity_R		0.72
gMVP		0.49

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

Publications

LitVar

Other links and lift over

dbSNP: rs864622202; hg19: chr17-29576039;