4-1807262-A-T

Variant names:

• chr4-1807262-A-T
• rs121913103
• ENST00000481110.7:c.2353A>T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_001354810.2(FGFR3):​c.2353A>T​(p.Lys785*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: FGFR3 NM_001354810.2 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:3 O:1
• Conservation: PhyloP100: 3.42

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 Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0109 CDS is truncated, and there are 2 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-1807262-A-T is Pathogenic according to our data. Variant chr4-1807262-A-T is described in ClinVar as [Pathogenic]. Clinvar id is 16336.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr4-1807262-A-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FGFR3	NM_000142.5	c.2421A>T	p.Ter807Cysext*?	stop_lost	Exon 18 of 18	ENST00000440486.8	NP_000133.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FGFR3	ENST00000440486.8	c.2421A>T	p.Ter807Cysext*?	stop_lost	Exon 18 of 18	5	NM_000142.5	ENSP00000414914.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Thanatophoric dysplasia type 1 Pathogenic:1 Other:1

-

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Apr 01, 1996

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

See cases Pathogenic:1

Nov 30, 2021

Institute Of Reproduction And Development, Obstetrics and Gynecology Hospital, Fudan University

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

FGFR3-related disorder Pathogenic:1

Sep 09, 2023

PreventionGenetics, part of Exact Sciences

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The FGFR3 c.2421A>T variant is predicted to result in extension of the open reading frame (p.*807Cysext*101). This variant was reported in individuals with thanatophoric dysplasia (Patient 2 in Rousseau et al. 1995. PubMed ID: 7647778; Soo-Kyeong et al. 2018. PubMed ID: 30252581). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. In ClinVar, this variant has been interpreted as pathogenic. In addition, other nucleotide changes at c.2421 (c.241A>C and c.241A>G), resulting in a stop loss and protein extension, have been reported in patients with thanatophoric dysplasia (Passos-Bueno et al. 1999. PubMed ID: 10425034).This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.054	T
BayesDel_noAF	Benign	-0.32
CADD	Benign	18
DANN	Uncertain	0.99
Eigen	Pathogenic	0.83
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Uncertain	0.94	D
Vest4		0.44
GERP RS		4.6

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

LitVar

Other links and lift over

dbSNP: rs121913103; hg19: chr4-1808989;