chr17-17228023-G-T

Position:

• chr17-17228023-G-T

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BS2_Supporting

The NM_144997.7(FLCN):​c.115C>A​(p.Pro39Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,580 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. 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. P39R) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: FLCN NM_144997.7 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 0.645

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 Likely_benign. Variant got -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.06972399).
• BS2: High AC in GnomAdExome4 at 5 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	UniProt
FLCN	NM_144997.7	c.115C>A	p.Pro39Thr	missense_variant	4/14	ENST00000285071.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FLCN	ENST00000285071.9	c.115C>A	p.Pro39Thr	missense_variant	4/14	1	NM_144997.7	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251216 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135878

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461580 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727098

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: 0.00000270

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jan 01, 2023	FLCN: PM2, BP4 -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jan 02, 2024	Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 25, 2023

The p.P39T variant (also known as c.115C>A), located in coding exon 1 of the FLCN gene, results from a C to A substitution at nucleotide position 115. The proline at codon 39 is replaced by threonine, an amino acid with highly similar properties. This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated 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

Jul 21, 2023

This sequence change replaces proline, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 39 of the FLCN protein (p.Pro39Thr). This variant is present in population databases (no rsID available, gnomAD 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. 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 tolerated. ClinVar contains an entry for this variant (Variation ID: 409408). This variant has not been reported in the literature in individuals affected with FLCN-related conditions. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.061
BayesDel_addAF	Benign	-0.0086	T
BayesDel_noAF	Benign	-0.25
CADD	Benign	9.8
DANN	Benign	0.71
DEOGEN2	Benign	0.19	T;.
Eigen	Benign	-0.57
Eigen_PC	Benign	-0.46
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Benign	0.73	T;T
M_CAP	Uncertain	0.10	D
MetaRNN	Benign	0.070	T;T
MetaSVM	Benign	-0.50	T
MutationAssessor	Benign	0.28	N;N
MutationTaster	Benign	0.64	N;N
PrimateAI	Benign	0.33	T
PROVEAN	Benign	-0.93	N;N
REVEL	Benign	0.23
Sift	Benign	0.36	T;T
Sift4G	Benign	0.41	T;T
Polyphen		0.0010	B;B
Vest4		0.12
MutPred		0.22		Gain of loop (P = 0.0312);Gain of loop (P = 0.0312);
MVP		0.31
MPC		0.41
ClinPred		0.091	T
GERP RS		2.5
Varity_R		0.028
gMVP		0.35

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: rs1060502375; hg19: chr17-17131337;