4-1805644-C-G

Variant names:

• chr4-1805644-C-G
• rs28933068
• NM_000142.5:c.1620C>G

Variant summary

Our verdict is Pathogenic. The variant received 26 ACMG points: 26P and 0B. PS1_Very_Strong PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000142.5(FGFR3):​c.1620C>G​(p.Asn540Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,882 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Pathogenic in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N540D) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: FGFR3 NM_000142.5 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:31 O:1
• Conservation: PhyloP100: 3.02
• Publications: 152 publications found

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)

ACMG classification

Our verdict: Pathogenic. The variant received 26 ACMG points.

• PS1: Transcript NM_000142.5 (FGFR3) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000142.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr4-1805642-A-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 374828.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 4-1805644-C-G is Pathogenic according to our data. Variant chr4-1805644-C-G is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 16338.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FGFR3	NM_000142.5	c.1620C>G	p.Asn540Lys	missense_variant	Exon 12 of 18	ENST00000440486.8	NP_000133.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FGFR3	ENST00000440486.8	c.1620C>G	p.Asn540Lys	missense_variant	Exon 12 of 18	5	NM_000142.5	ENSP00000414914.2

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460882 Hom.: 0 Cov.: 34 AF XY: 0.00000275 AC XY: 2 AN XY: 726810

African (AFR) AF: 0.00 AC: 0 AN: 33460

American (AMR) AF: 0.00 AC: 0 AN: 44698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26108

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.0000189 AC: 1 AN: 52828

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111718

Other (OTH) AF: 0.00 AC: 0 AN: 60360

GnomAD4 genome Cov.: 34

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:31 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:11

May 31, 2018

Clinical Genetics and Genomics, Karolinska University Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Feb 16, 2025

Laboratory of Genetics, Children's Clinical University Hospital Latvia

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 01, 2022

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

FGFR3: PS4, PM2, PM6, PP3, PP4 -

Nov 30, 2019

Blueprint Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 17, 2022

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Observed in multiple individuals with hypochondroplasia in the published literature (Prinos et al., 1995; Foldynova-Trantirkova et al., 2012); Published functional studies demonstrate this variant results in significantly reduced in vitro expression (Raffioni et al., 1998); Not observed in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 8640234, 29681095, 10360392, 22045636, 23149434, 9857065, 23165795, 11754059, 19088846, 8589686, 28777845, 29478821, 29150894, 17621485, 29620724, 30355600, 26380986, 34567078, 33942288, 32712949, 33389251) -

-

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jan 18, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces asparagine, which is neutral and polar, with lysine, which is basic and polar, at codon 540 of the FGFR3 protein (p.Asn540Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with hypochondroplasia or achondroplasia (PMID: 7670477, 8589686, 9452043, 10360392, 11055896, 11754059, 23149434, 23165795, 25614871). ClinVar contains an entry for this variant (Variation ID: 16338). Invitae Evidence Modeling incorporating data from in vitro experimental studies (internal data) indicates that this missense variant is expected to disrupt FGFR3 function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects FGFR3 function (PMID: 19088846). For these reasons, this variant has been classified as Pathogenic. -

Apr 05, 2018

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Sep 23, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The FGFR3 c.1620C>G; p.Asn540Lys variant (rs28933068) is a recurrent alteration in patients with hypochondroplasia (Camera 2001, Kannu 2007, Korkmaz 2012, Linnankivi 2012, Xue 2014). Another variant at this position, c.1620C>A, also results in the same amino acid alteration (p.Asn540Lys), and is the most common pathogenic variant in hypochondroplasia patients (Xue 2014). Functional characterization of the variant protein indicates increased phosphorylation of ERK1/2, resulting in an over-activation of the MAPK signaling pathway (Krejci 2008). The c.1620C>G; p.Asn540Lys variant is reported in ClinVar (Variation ID: 16338). It is absent from the Genome Aggregation Database, indicating it is not a common polymorphism. Based on available information, the p.Asn540Lys variant is considered to be pathogenic. References: Camera G et al. Occurrence of thanatophoric dysplasia type I (R248C) and hypochondroplasia (N540K) mutations in two patients with achondroplasia phenotype. Am J Med Genet. 2001; 104(4):277-81. PMID: 11754059. Kannu P et al. FGFR3 mutations and medial temporal lobe dysgenesis. J Child Neurol. 2007; 22(2):211-3. PMID: 17621485. Korkmaz HA et al. Hypochondroplasia in a child with 1620C>G (Asn540Lys) mutation in FGFR3. J Clin Res Pediatr Endocrinol. 2012; 4(4):220-2. PMID: 23149434. Krejci P et al. Analysis of STAT1 activation by six FGFR3 mutants associated with skeletal dysplasia undermines dominant role of STAT1 in FGFR3 signaling in cartilage. PLoS One. 2008; 3(12):e3961. PMID: 19088846. Linnankivi T et al. Neuroimaging and neurological findings in patients with hypochondroplasia and FGFR3 N540K mutation. Am J Med Genet A. 2012; 158A(12):3119-25. PMID: 23165795. Xue Y et al. FGFR3 mutation frequency in 324 cases from the International Skeletal Dysplasia Registry. Mol Genet Genomic Med. 2014; 2(6):497-503. PMID: 25614871. -

-

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Hypochondroplasia Pathogenic:9 Other:1

Dec 24, 2024

Hacettepe Pediatric Genetics Laboratory, Hacettepe University

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The FGFR3 c.1620C>G variant (p.Asn540Lys) was classified as "pathogenic" according to the ACMG criteria 2019. This variant was assessed as deleterious according to the SIFT prediction program (score 0) and the Mutation Taster prediction program (score 1).The Asn540Lys variant in FGFR3 has been reported in a Turkish patient with Hypochondroplasia (https://doi.org/10.4274/jcrpe.787). In summary, the Asn540Lys variant meets our criteria to be classified as pathogenic. -

Apr 01, 2015

Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

- -

Dec 30, 2021

Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ACMG classification criteria: PS1 strong, PS3 supporting, PS4 strong, PM2 moderate -

Apr 06, 2016

Clinical Molecular Genetics Laboratory, Johns Hopkins All Children's Hospital

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Feb 01, 2024

Department of Pediatrics, Taizhou Central Hospital, Taizhou University Hospital

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Apr 01, 1999

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

May 09, 2022

Kasturba Medical College, Manipal, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 01, 2023

Clinical Laboratory Sciences Program (CLSP), King Saud bin Abdulaziz University for Health Sciences (KSAU-HS)

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Sep 18, 2017

Bioscientia Institut fuer Medizinische Diagnostik GmbH, Sonic Healthcare

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

Most common pathogenic variant in hypochondroplasia -

Achondroplasia Pathogenic:4

Feb 14, 2020

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was determined to be pathogenic according to ACMG Guidelines, 2015 [PMID:25741868]. -

Dec 19, 2023

3billion

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The variant is not observed in the gnomAD v2.1.1 dataset. Predicted Consequence/Location: Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product [REVEL: 0.69 (>=0.6, sensitivity 0.68 and specificity 0.92); 3Cnet: 0.76 (>=0.6, sensitivity 0.72 and precision 0.9)]. Same nucleotide change resulting in same amino acid change (ClinVar ID: VCV000016338 /PMID: 8589686) and different missense changes at the same codon (p.Asn540Asp, p.Asn540His, p.Asn540Ser, p.Asn540Thr / ClinVar ID: VCV000016344, VCV000016349, VCV000374828, VCV001325830 /PMID: 10777366, 9452043) have been previously reported as pathogenic/likely pathogenic with strong evidence.The variant has been observed in at least two similarly affected unrelated individuals (PMID: 25614871). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -

Aug 07, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: FGFR3 c.1620C>G (p.Asn540Lys) results in a non-conservative amino acid change located in the Protein kinase domain (IPR000719) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 250610 control chromosomes (gnomAD). c.1620C>G has been reported in the literature in multiple individuals affected with Hypochondroplasia, in some cases as a de novo occurrence (e.g. Maddirevula_2018, Zhu_2022). These data indicate that the variant is very likely to be associated with disease. A different variant affecting the same codon has been classified as pathogenic by our lab (c.1619A>G, p.Asn540Ser), supporting the critical relevance of codon 540 to FGFR3 protein function. The following publications have been ascertained in the context of this evaluation (PMID: 29620724, 35726512). ClinVar contains an entry for this variant (Variation ID: 16338). Based on the evidence outlined above, the variant was classified as pathogenic. -

Jul 27, 2022

MGZ Medical Genetics Center

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Achondroplasia;C0005684:Malignant tumor of urinary bladder;C0153594:Malignant tumor of testis;C0265269:Levy-Hollister syndrome;C0334082:Epidermal nevus;C0410529:Hypochondroplasia;C0699790:Carcinoma of colon;C1300257:Thanatophoric dysplasia, type 2;C1864436:Muenke syndrome;C1864852:Camptodactyly-tall stature-scoliosis-hearing loss syndrome;C1868678:Thanatophoric dysplasia type 1;C2674173:Severe achondroplasia-developmental delay-acanthosis nigricans syndrome;C2677099:Crouzon syndrome-acanthosis nigricans syndrome;C4048328:Cervical cancer Pathogenic:1

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Inborn genetic diseases Pathogenic:1

Sep 19, 2016

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

FGFR3-related disorder Pathogenic:1

Aug 26, 2024

PreventionGenetics, part of Exact Sciences

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The FGFR3 c.1620C>G variant is predicted to result in the amino acid substitution p.Asn540Lys. This variant has been reported to be the most common cause of hypochondroplasia (Bellus et al. 1995. PubMed ID: 7670477; Prinos et al. 1995. PubMed ID: 8589686). Additionally, functional studies support its pathogenicity (Raffioni et al. 1998. PubMed ID: 9857065). This variant has not been reported in a large population database, indicating it is rare. This variant is interpreted as pathogenic. -

Larsen syndrome Pathogenic:1

Dec 25, 2021

Kasturba Medical College, Manipal, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Short stature Pathogenic:1

Jun 23, 2015

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Connective tissue disorder Pathogenic:1

Jul 01, 2020

Genome Diagnostics Laboratory, The Hospital for Sick Children

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Achondroplasia;C0005684:Malignant tumor of urinary bladder;C0334082:Epidermal nevus;C0346629:Colorectal cancer;C0410529:Hypochondroplasia;C1300257:Thanatophoric dysplasia, type 2;C1336708:Germ cell tumor of testis;C1864436:Muenke syndrome;C1864852:Camptodactyly-tall stature-scoliosis-hearing loss syndrome;C1868678:Thanatophoric dysplasia type 1;C2674173:Severe achondroplasia-developmental delay-acanthosis nigricans syndrome;C2677099:Crouzon syndrome-acanthosis nigricans syndrome;C4048328:Cervical cancer;C5774286:Lacrimoauriculodentodigital syndrome 2 Pathogenic:1

-

Juno Genomics, Hangzhou Juno Genomics, Inc

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PM2_Supporting+PS4+PS2+PS3_Moderate+PS1 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.060
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.89	D;D;.;.;.
Eigen	Benign	0.15
Eigen_PC	Benign	0.16
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.94	D;D;D;D;.
M_CAP	Pathogenic	0.91	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D
MetaSVM	Uncertain	0.18	D
MutationAssessor	Benign	-0.10	N;.;.;.;.
PhyloP100		3.0
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.3	D;D;D;D;D
REVEL	Pathogenic	0.69
Sift	Pathogenic	0.0	D;D;D;D;D
Sift4G	Uncertain	0.0020	D;D;D;D;D
Polyphen		1.0	D;D;D;D;D
Vest4		1.0
MutPred		0.90		Gain of methylation at N540 (P = 0.007);.;.;.;.;
MVP		0.95
MPC		1.0
ClinPred		1.0	D
GERP RS		3.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.81
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs28933068; hg19: chr4-1807371;