17-31181750-C-T

Variant names:

• chr17-31181750-C-T
• rs769719064
• NM_001042492.3:c.695C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001042492.3(NF1):​c.695C>T​(p.Thr232Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000138 in 1,449,544 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. T232A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: NF1 NM_001042492.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 7.09
• Publications: 3 publications found

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 Gene-Disease associations (from GenCC):

• neurofibromatosis type 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, PanelApp Australia, G2P, Genomics England PanelApp
• neurofibromatosis-Noonan syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, PanelApp Australia
• Moyamoya disease

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• hereditary pheochromocytoma-paraganglioma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial ovarian cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

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

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001042492.3. 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
	NF1	NM_001042492.3	MANE Select	c.695C>T	p.Thr232Ile	missense	Exon 7 of 58	NP_001035957.1
	NF1	NM_000267.4		c.695C>T	p.Thr232Ile	missense	Exon 7 of 57	NP_000258.1
	NF1	NM_001128147.3		c.695C>T	p.Thr232Ile	missense	Exon 7 of 15	NP_001121619.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NF1	ENST00000358273.9	TSL:1 MANE Select	c.695C>T	p.Thr232Ile	missense	Exon 7 of 58	ENSP00000351015.4
	NF1	ENST00000356175.7	TSL:1	c.695C>T	p.Thr232Ile	missense	Exon 7 of 57	ENSP00000348498.3
	NF1	ENST00000431387.8	TSL:1	c.695C>T	p.Thr232Ile	missense	Exon 7 of 15	ENSP00000412921.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251234 AF XY: 0.00

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000138 AC: 2 AN: 1449544 Hom.: 0 Cov.: 29 AF XY: 0.00000139 AC XY: 1 AN XY: 721584

African (AFR) AF: 0.00 AC: 0 AN: 33372

American (AMR) AF: 0.00 AC: 0 AN: 44672

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25980

East Asian (EAS) AF: 0.00 AC: 0 AN: 39494

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86004

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53280

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5580

European-Non Finnish (NFE) AF: 9.08e-7 AC: 1 AN: 1101278

Other (OTH) AF: 0.00 AC: 0 AN: 59884

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Neurofibromatosis, type 1 Uncertain:3

Jun 15, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 232 of the NF1 protein (p.Thr232Ile). This variant is present in population databases (rs769719064, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with NF1-related conditions. ClinVar contains an entry for this variant (Variation ID: 527575). 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 expected to disrupt NF1 protein function.

Mar 15, 2022

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Mar 26, 2024

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Uncertain:1

Apr 18, 2018

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is denoted NF1 c.695C>T at the cDNA level, p.Thr232Ile (T232I) at the protein level, and results in the change of a Threonine to an Isoleucine (ACA>ATA). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. NF1 Thr232Ile was observed at an allele frequency of 0.003% (1/30,768) in individuals of South Asian ancestry in large population cohorts (Lek 2016). This variant is not located in a known functional domain. In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect. Based on currently available evidence, it is unclear whether NF1 Thr232Ile is a pathogenic or benign variant. We consider it to be a variant of uncertain significance.

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

Aug 21, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T232I variant (also known as c.695C>T), located in coding exon 7 of the NF1 gene, results from a C to T substitution at nucleotide position 695. The threonine at codon 232 is replaced by isoleucine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.72
BayesDel_addAF	Pathogenic	0.23	D
BayesDel_noAF	Pathogenic	0.20
CADD	Uncertain	24
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.74	D
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.52	D
MetaRNN	Uncertain	0.65	D
MetaSVM	Uncertain	0.14	D
MutationAssessor	Benign	2.0	M
PhyloP100		7.1
PrimateAI	Pathogenic	0.80	T
PROVEAN	Uncertain	-2.7	D
REVEL	Uncertain	0.55
Sift	Benign	0.11	T
Sift4G	Benign	0.17	T
Polyphen		1.0	D
Vest4		0.67
MutPred		0.28		Gain of helix (P = 0.132)
MVP		0.81
MPC		1.8
ClinPred		0.88	D
GERP RS		5.9
PromoterAI		-0.017	Neutral
Varity_R		0.37
gMVP		0.52
Mutation Taster		=19/81	disease causing

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: rs769719064; hg19: chr17-29508768;