8-16993162-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_019851.3(FGF20):c.546G>C(p.Lys182Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000658 in 152,080 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: FGF20 NM_019851.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.59

Genes affected

FGF20 (HGNC:3677): (fibroblast growth factor 20) The protein encoded by this gene is a member of the fibroblast growth factor family. The fibroblast growth factors possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. This gene product is a secreted neurotrophic factor but lacks a typical signal peptide. It is expressed in normal brain, particularly the cerebellum, and may regulate central nervous system development and function. Homodimerization of this protein was shown to regulate its receptor binding activity and concentration gradient in the extracellular matrix. Genetic variations of this gene have been associated with Parkinson disease susceptibility. [provided by RefSeq, Oct 2009]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FGF20	NM_019851.3	c.546G>C	p.Lys182Asn	missense_variant	3/3	ENST00000180166.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FGF20	ENST00000180166.6	c.546G>C	p.Lys182Asn	missense_variant	3/3	1	NM_019851.3	P1
FGF20	ENST00000519941.1	c.252G>C	p.Lys84Asn	missense_variant	2/2	5

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152080 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152080 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74284

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 10, 2023

This sequence change replaces lysine, which is basic and polar, with asparagine, which is neutral and polar, at codon 182 of the FGF20 protein (p.Lys182Asn). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with FGF20-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Benign	-0.074	T
BayesDel_noAF	Benign	-0.34
Cadd	Uncertain	24
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.78	D
Eigen	Benign	0.050
Eigen_PC	Benign	0.084
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.96	D
M_CAP	Uncertain	0.089	D
MetaRNN	Uncertain	0.42	T
MetaSVM	Uncertain	0.022	D
MutationAssessor	Uncertain	2.3	M
MutationTaster	Benign	0.98	D
PrimateAI	Uncertain	0.73	T
PROVEAN	Uncertain	-3.7	D
REVEL	Uncertain	0.44
Sift	Benign	0.040	D
Sift4G	Uncertain	0.010	D
Polyphen		0.67	P
Vest4		0.26
MutPred		0.47		Loss of methylation at K182 (P = 0.0084);
MVP		0.66
MPC		0.012
ClinPred		0.99	D
GERP RS		3.1
Varity_R		0.84
gMVP		0.53

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: rs1809955799; hg19: chr8-16850671;