chr17-17222628-G-A

Position:

• chr17-17222628-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PP3_Moderate BS2_Supporting

The NM_144997.7(FLCN):​c.652C>T​(p.Arg218Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000479 in 1,461,884 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 Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: FLCN NM_144997.7 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 5.55

Genes affected

FLCN (HGNC:27310): (folliculin) This gene is located within the Smith-Magenis syndrome region on chromosome 17. Mutations in this gene are associated with Birt-Hogg-Dube syndrome, which is characterized by fibrofolliculomas, renal tumors, lung cysts, and pneumothorax. Alternative splicing of this gene results in two transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

ENSG00000264187 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a domain uDENN FLCN/SMCR8-type (size 156) in uniprot entity FLCN_HUMAN there are 14 pathogenic changes around while only 2 benign (88%) in NM_144997.7
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.841
• BS2: High AC in GnomAdExome4 at 7 AD gene. Variant has AC lower than other variant known as pathogenic in the gene, so the strength is limited to Supporting.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FLCN	NM_144997.7	c.652C>T	p.Arg218Cys	missense_variant	7/14	ENST00000285071.9	NP_659434.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FLCN	ENST00000285071.9	c.652C>T	p.Arg218Cys	missense_variant	7/14	1	NM_144997.7	ENSP00000285071.4
ENSG00000264187	ENST00000427497.3	n.149-3574C>T		intron_variant		1		ENSP00000394249.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461884 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727244

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: 0.00000540

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Colorectal cancer;C1868193:Familial spontaneous pneumothorax;CN074294:Nonpapillary renal cell carcinoma;CN375946:Birt-Hogg-Dube syndrome 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Jan 02, 2024

- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 01, 2024

The p.R218C variant (also known as c.652C>T), located in coding exon 4 of the FLCN gene, results from a C to T substitution at nucleotide position 652. The arginine at codon 218 is replaced by cysteine, an amino acid with highly dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Birt-Hogg-Dube syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 18, 2024

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 218 of the FLCN protein (p.Arg218Cys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with FLCN-related conditions. ClinVar contains an entry for this variant (Variation ID: 460626). 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) performed at Invitae indicates that this missense variant is not expected to disrupt FLCN protein function with a negative predictive value of 80%. 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	0.95
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.30
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.95	D;.
Eigen	Pathogenic	0.75
Eigen_PC	Pathogenic	0.74
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Uncertain	0.19	D
MetaRNN	Pathogenic	0.84	D;D
MetaSVM	Uncertain	0.70	D
MutationAssessor	Uncertain	2.0	M;M
PrimateAI	Pathogenic	0.86	D
PROVEAN	Uncertain	-3.7	D;D
REVEL	Pathogenic	0.71
Sift	Uncertain	0.0030	D;D
Sift4G	Uncertain	0.013	D;D
Polyphen		1.0	D;D
Vest4		0.89
MutPred		0.51		Loss of disorder (P = 0.0502);Loss of disorder (P = 0.0502);
MVP		0.62
MPC		1.3
ClinPred		0.99	D
GERP RS		5.7
RBP_binding_hub_radar		0.92
RBP_regulation_power_radar		2.6
Varity_R		0.80
gMVP		0.62

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: rs1555609896; hg19: chr17-17125942;