17-31327839-G-C

Position:

• chr17-31327839-G-C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5

The NM_001042492.3(NF1):​c.5609G>C​(p.Arg1870Pro) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 14/25 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. 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. R1870Q) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: NF1 NM_001042492.3 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 9.56

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]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 14 uncertain in NM_001042492.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-31327839-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 185354.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, NF1
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.
• PP5: Variant 17-31327839-G-C is Pathogenic according to our data. Variant chr17-31327839-G-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 1748220.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=1}. Variant chr17-31327839-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NF1	NM_001042492.3	c.5609G>C	p.Arg1870Pro	missense_variant, splice_region_variant	38/58	ENST00000358273.9
NF1	NM_000267.3	c.5546G>C	p.Arg1849Pro	missense_variant, splice_region_variant	37/57

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NF1	ENST00000358273.9	c.5609G>C	p.Arg1870Pro	missense_variant, splice_region_variant	38/58	1	NM_001042492.3	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 31

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Neurofibromatosis, type 1 Pathogenic:1 Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Aug 17, 2023	This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 1849 of the NF1 protein (p.Arg1849Pro). This variant also falls at the last nucleotide of exon 37, which is part of the consensus splice site for this exon. This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of neurofibromatosis type 1 (PMID: 23913538). ClinVar contains an entry for this variant (Variation ID: 1748220). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This variant disrupts the c.5546G nucleotide in the NF1 gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 10607834, 10980545, 27322474; Invitae). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position 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. -
Pathogenic, no assertion criteria provided	research	Department of Medical Genetics, College of Basic Medicine, Army Medical University	-	- -

Hereditary cancer-predisposing syndrome;CN230736:Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 09, 2022

The c.5546G>C variant (also known as p.R1849P), located in coding exon 37 of the NF1 gene, results from a G to C substitution at nucleotide position 5546. The amino acid change results in arginine to proline at codon 1849, an amino acid with dissimilar properties. However, this change occurs in the last base pair of coding exon 37, which makes it likely to have some effect on normal mRNA splicing. This variant was identified in 1 of 565 unrelated French probands with clinical diagnoses or suspicion of neurofibromatosis type 1 (Sabbagh A et al. Hum Mutat, 2013 Nov;34:1510-8). In silico splice site analysis predicts that this alteration may weaken the native splice donor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	35
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D;.;D;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.96	D;D;D;D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.90	D;D;D;D
MetaSVM	Uncertain	-0.18	T
MutationAssessor	Pathogenic	3.3	M;.;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-6.0	D;D;D;.
REVEL	Pathogenic	0.79
Sift	Pathogenic	0.0	D;D;D;.
Sift4G	Pathogenic	0.0	D;D;D;.
Polyphen		1.0	D;D;.;.
Vest4		0.98
MutPred		0.62		Gain of glycosylation at R1870 (P = 0.01);.;.;.;
MVP		0.93
MPC		2.7
ClinPred		1.0	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.95
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.39		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.39		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr17-29654857;