rs1555608487

Positions:

• chr17-17219039-A-T

Variant summary

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

The NM_144997.7(FLCN):​c.1042T>A​(p.Ser348Thr) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S348Y) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: FLCN NM_144997.7 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.27

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]

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
FLCN	NM_144997.7	c.1042T>A	p.Ser348Thr	missense_variant	9/14	ENST00000285071.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FLCN	ENST00000285071.9	c.1042T>A	p.Ser348Thr	missense_variant	9/14	1	NM_144997.7	P1
FLCN	ENST00000577591.1	n.65T>A		non_coding_transcript_exon_variant	1/2	2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 23, 2020

The p.S348T variant (also known as c.1042T>A), located in coding exon 6 of the FLCN gene, results from a T to A substitution at nucleotide position 1042. The serine at codon 348 is replaced by threonine, an amino acid with similar 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

Invitae

Apr 10, 2020

This variant is not present in population databases (ExAC no frequency). 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with FLCN-related disease. This sequence change replaces serine with threonine at codon 348 of the FLCN protein (p.Ser348Thr). The serine residue is highly conserved and there is a small physicochemical difference between serine and threonine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.55	D
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.67	T
M_CAP	Uncertain	0.18	D
MetaRNN	Uncertain	0.69	D
MetaSVM	Uncertain	0.65	D
MutationAssessor	Benign	1.8	L
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.67	T
PROVEAN	Benign	-1.3	N
REVEL	Uncertain	0.58
Sift	Benign	0.12	T
Sift4G	Benign	0.21	T
Polyphen		0.96	D
Vest4		0.66
MutPred		0.35		Gain of helix (P = 0.0696);
MVP		0.61
MPC		0.57
ClinPred		0.83	D
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.38
gMVP		0.65

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: rs1555608487; hg19: chr17-17122353;