chr4-1807261-G-T

Position:

• chr4-1807261-G-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM2 PM4 PP5_Very_Strong

The NM_000142.5(FGFR3):​c.2420G>T​(p.Ter807Leuext*?) variant causes a stop lost 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)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: FGFR3 NM_000142.5 stop_lost
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 2.86

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Stoplost variant in NM_000142.5 Downstream stopcodon found after 897 codons.
• PP5: Variant 4-1807261-G-T is Pathogenic according to our data. Variant chr4-1807261-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 65562.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FGFR3	NM_000142.5	c.2420G>T	p.Ter807Leuext*?	stop_lost	18/18	ENST00000440486.8	NP_000133.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FGFR3	ENST00000440486.8	c.2420G>T	p.Ter807Leuext*?	stop_lost	18/18	5	NM_000142.5	ENSP00000414914.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1445614 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 718418

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Aug 08, 2022	Variant resulting in loss of the termination codon leading to protein extension by 101 amino acids; Identified in patients with thanatophoric dysplaisa in published literature (Passos-Bueno et al., 1999); Multiple other variants resulting in loss of termination codon and protein extension reported in association with thanatophoric dysplasia (HGMD); Several different variants resulting in similar protein extensions have been reported in the Human Gene Mutation Database associated with thanatophoric dysplasia (HGMD), and have apparently similar functional consequences on protein stability and/or processing (Bonaventure et al., 2007; Gibbs et al., 2007); Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 25614871, 25728633, 20301540, 33942288, 9677066, 10425034, 17509076, 17320202) -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 14, 2020	For these reasons, this variant has been classified as Pathogenic. Several other stop codon variants (p.*807Glyext*101, p.*807Argext*101, p.*807Cysext*101) have also been described in individuals with thanatophoric dysplasia type I, which result in the same length of a cysteine-rich, highly hydrophobic elongation at the C-terminus of FGFR3 protein (PMID: 7647778, 25614871). In addition, one of these variants (p.*807Argext*101) has been reported to disrupt the protein function and determined to be pathogenic (PMID: 17509076). This variant has been reported in the literature in individuals affected with thanatophoric dysplasia type I (PMID: 10425034, 25728633). This variant is also known as X807L and *807Leuext*102 in the literature. ClinVar contains an entry for this variant (Variation ID: 65562). This variant is not present in population databases (ExAC no frequency). This sequence change disrupts the translational stop signal of the FGFR3 mRNA. It is expected to replace the original stop signal with a leucine residue and extend the length of the FGFR3 protein by 101 additional amino acid residues (p.*807Leuext*101). -

Achondroplasia;C0005684:Malignant tumor of urinary bladder;C0265269:Levy-Hollister syndrome;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 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Feb 14, 2022

- -

Thanatophoric dysplasia type 1 Other:1

not provided, no classification provided

literature only

GeneReviews

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.21	T
BayesDel_noAF	Benign	-0.55
CADD	Benign	18
DANN	Benign	0.79
Eigen	Pathogenic	0.88
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Uncertain	0.91	D
Vest4		0.35
GERP RS		3.7

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: rs397515514; hg19: chr4-1808988;