4-1804477-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2BP6

The NM_000142.5(FGFR3):c.1223C>T(p.Ser408Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,612,888 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. S408S) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 34)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

FGFR3
NM_000142.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: 4.54

Publications

6 publications found

Variant links:

Genes affected

FGFR3 (HGNC:3690): (fibroblast growth factor receptor 3) This gene encodes a member of the fibroblast growth factor receptor (FGFR) family, with its amino acid sequence being highly conserved between members and among divergent species. FGFR family members differ from one another in their ligand affinities and tissue distribution. A full-length representative protein would consist of an extracellular region, composed of three immunoglobulin-like domains, a single hydrophobic membrane-spanning segment and a cytoplasmic tyrosine kinase domain. The extracellular portion of the protein interacts with fibroblast growth factors, setting in motion a cascade of downstream signals, ultimately influencing mitogenesis and differentiation. This particular family member binds acidic and basic fibroblast growth hormone and plays a role in bone development and maintenance. Mutations in this gene lead to craniosynostosis and multiple types of skeletal dysplasia. [provided by RefSeq, Aug 2017]

FGFR3 Gene-Disease associations (from GenCC):

achondroplasia
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, ClinGen, Genomics England PanelApp, Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
Crouzon syndrome-acanthosis nigricans syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Orphanet, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), PanelApp Australia, ClinGen
hypochondroplasia
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, G2P, ClinGen, Labcorp Genetics (formerly Invitae), Orphanet
lacrimoauriculodentodigital syndrome 2
Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
Muenke syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Ambry Genetics, PanelApp Australia, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, ClinGen, G2P
thanatophoric dysplasia type 1
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Genomics England PanelApp, Orphanet, ClinGen
thanatophoric dysplasia type 2
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, ClinGen, Genomics England PanelApp, G2P, Labcorp Genetics (formerly Invitae)
camptodactyly-tall stature-scoliosis-hearing loss syndrome
Inheritance: AR, AD, SD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE, LIMITED Submitted by: Ambry Genetics, G2P, Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
severe achondroplasia-developmental delay-acanthosis nigricans syndrome
Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen
isolated brachycephaly
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
isolated plagiocephaly
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
LADD syndrome
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
LADD syndrome 1
Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

FGFR3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP6

Variant 4-1804477-C-T is Benign according to our data. Variant chr4-1804477-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 255326.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FGFR3	NM_000142.5 link	c.1223C>T	p.Ser408Phe	missense_variant	Exon 9 of 18	ENST00000440486.8	NP_000133.1	P22607-1Q0IJ44

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FGFR3	ENST00000440486.8 link	c.1223C>T	p.Ser408Phe	missense_variant	Exon 9 of 18	5	NM_000142.5	ENSP00000414914.2		P22607-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000400

AC:

AN:

249900

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1460716

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726682

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52384

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111914

Other (OTH)

AF:

0.00

AC:

AN:

60370

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74340

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41434

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.725

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Mar 20, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1223C>T (p.S408F) alteration is located in exon 9 (coding exon 8) of the FGFR3 gene. This alteration results from a C to T substitution at nucleotide position 1223, causing the serine (S) at amino acid position 408 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Jan 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces serine, which is neutral and polar, with phenylalanine, which is neutral and non-polar, at codon 408 of the FGFR3 protein (p.Ser408Phe). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with FGFR3-related conditions. ClinVar contains an entry for this variant (Variation ID: 255326). 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 not expected to disrupt FGFR3 protein function with a negative predictive value of 95%. 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. -

not specified

Benign:1

PreventionGenetics, part of Exact Sciences

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Uncertain

0.076

BayesDel_noAF

Benign

-0.13

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.65

D;T;.

Eigen

Uncertain

0.34

Eigen_PC

Uncertain

0.36

FATHMM_MKL

Uncertain

0.96

LIST_S2

Uncertain

0.96

D;D;D

M_CAP

Pathogenic

0.43

MetaRNN

Uncertain

0.44

T;T;T

MetaSVM

Uncertain

0.32

MutationAssessor

Benign

1.0

L;.;.

PhyloP100

4.5

PrimateAI

Benign

0.47

PROVEAN

Benign

-2.2

N;N;N

REVEL

Uncertain

0.47

Sift

Uncertain

0.012

D;D;D

Sift4G

Uncertain

0.054

T;T;T

Polyphen

0.84

P;D;P

Vest4

0.36

MutPred

0.38

Loss of disorder (P = 0.0028);Loss of disorder (P = 0.0028);.;

MVP

0.94

MPC

0.65

ClinPred

0.65

GERP RS

4.4

Varity_R

0.20

gMVP

0.54

Mutation Taster

=52/48

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over