rs121913110

chr4-1805643-A-Gchr4-1805643-A-C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_000142.5(FGFR3):c.1619A>G(p.Asn540Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,613,096 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 Conflicting classifications of pathogenicity (no stars). 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: 𝑓 0.000020 (0 hom., cov: 34)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: FGFR3 NM_000142.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:8 U:1
• Conservation: PhyloP100: 8.73

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]

ACMG classification

Verdict is Pathogenic. Variant got 11 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, 3 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 chr4-1805644-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 16338.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 4-1805643-A-G is Pathogenic according to our data. Variant chr4-1805643-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 16349.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=7, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FGFR3	NM_000142.5	c.1619A>G	p.Asn540Ser	missense_variant	12/18	ENST00000440486.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FGFR3	ENST00000440486.8	c.1619A>G	p.Asn540Ser	missense_variant	12/18	5	NM_000142.5	P4

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152216 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.0000241

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250598 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135696

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000164

GnomAD4 exome AF: 0.0000130 AC: 19 AN: 1460880 Hom.: 0 Cov.: 34 AF XY: 0.0000193 AC XY: 14 AN XY: 726800

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000383

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000379

Gnomad4 NFE exome AF: 0.0000117

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152216 Hom.: 0 Cov.: 34 AF XY: 0.0000134 AC XY: 1 AN XY: 74364

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000113

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:8 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jun 14, 2022	Not observed at a significant frequency in large population cohorts (gnomAD); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 29542187, 10777366, 23045425, 15909185, 12707965) -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Nov 14, 2023	This sequence change replaces asparagine, which is neutral and polar, with serine, which is neutral and polar, at codon 540 of the FGFR3 protein (p.Asn540Ser). This variant is present in population databases (rs77722678, gnomAD no frequency). This missense change has been observed in individuals with hypochondroplasia (PMID: 10777366, 12707965, 23045425). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 16349). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on FGFR3 protein function. This variant disrupts the p.Asn540 amino acid residue in FGFR3. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 11055896, 23165795, 25614871). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Clinical Genetics and Genomics, Karolinska University Hospital	Mar 28, 2018	- -

Hypochondroplasia Pathogenic:2

Pathogenic, no assertion criteria provided	literature only	OMIM	May 15, 2003	- -
Pathogenic, criteria provided, single submitter	clinical testing	3billion	Feb 23, 2023	The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: <0.001%). Missense changes are a common disease-causing mechanism. In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.78; 3Cnet: 0.55). Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000016349). Different missense changes at the same codon (p.Asn540Asp, p.Asn540His, p.Asn540Lys, p.Asn540Thr) have been reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000016337, VCV000016338, VCV000016344, VCV000374828, VCV001325830). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -

Achondroplasia Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Suma Genomics	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 28, 2022	Variant summary: FGFR3 c.1619A>G (p.Asn540Ser) results in a conservative amino acid change located in the Protein kinase domain (IPR000719) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 250598 control chromosomes. c.1619A>G has been reported in the literature in multiple families affected with Hypochondroplasia and shown to segregate with disease (deSanctis_2012, Mortier_2000, Thauvin-Robinet_2003). These data indicate that the variant is very likely to be associated with disease. Other variants at this amino acid, N540K and N540T have also been reported to associate with Hypochondroplasia in the literature. At least one publication reports experimental evidence evaluating an impact on protein function (Patani_2016). These results showed a 10 fold increase in auto-phosphorylation and a 2 fold increase in substrate phosphorylation. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified as VUS (n=1) and Pathogenic (n=3). Based on the evidence outlined above, the variant was classified as pathogenic. -

Neurodevelopmental delay Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Centre de Biologie Pathologie Génétique, Centre Hospitalier Universitaire de Lille

-

- -

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 25, 2016

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.20
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	-0.050
Cadd	Uncertain	25
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	D;D;.;.;.
Eigen	Uncertain	0.47
Eigen_PC	Uncertain	0.51
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	D;D;D;D;.
M_CAP	Pathogenic	0.83	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D
MetaSVM	Uncertain	0.59	D
MutationAssessor	Benign	0.44	N;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Uncertain	0.75	T
PROVEAN	Pathogenic	-4.4	D;D;D;D;D
REVEL	Pathogenic	0.78
Sift	Pathogenic	0.0	D;D;D;D;D
Sift4G	Uncertain	0.026	D;T;D;D;D
Polyphen		1.0	D;D;D;D;D
Vest4		0.91
MutPred		0.94		Loss of sheet (P = 0.1398);.;.;.;.;
MVP		0.95
MPC		0.83
ClinPred		1.0	D
GERP RS		4.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.81
gMVP		0.63

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs77722678; hg19: chr4-1807370;