17-17223983-C-T

Variant names:

• chr17-17223983-C-T
• rs876658409
• NM_144997.7:c.557G>A

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_144997.7(FLCN):​c.557G>A​(p.Trp186*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: FLCN NM_144997.7 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 7.37
• Publications: 3 publications found

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]

FLCN Gene-Disease associations (from GenCC):

• Birt-Hogg-Dube syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet, ClinGen
• Birt-Hogg-Dube syndrome 1

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P, Ambry Genetics
• familial spontaneous pneumothorax

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, Ambry Genetics
• renal carcinoma

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• colorectal cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics

ENSG00000264187 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 17-17223983-C-T is Pathogenic according to our data. Variant chr17-17223983-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 230137.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FLCN	NM_144997.7	c.557G>A	p.Trp186*	stop_gained	Exon 6 of 14	ENST00000285071.9	NP_659434.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FLCN	ENST00000285071.9	c.557G>A	p.Trp186*	stop_gained	Exon 6 of 14	1	NM_144997.7	ENSP00000285071.4
ENSG00000264187	ENST00000427497.3	n.148+4007G>A		intron_variant	Intron 4 of 11	1		ENSP00000394249.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Apr 17, 2017

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The W186X nonsense variant in the FLCN gene has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. Based on currently available evidence, we consider W186X to be pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Apr 19, 2018

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.W186* pathogenic mutation (also known as c.557G>A), located in coding exon 3 of the FLCN gene, results from a G to A substitution at nucleotide position 557. This changes the amino acid from a tryptophan to a stop codon within coding exon 3. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Birt-Hogg-Dube syndrome Pathogenic:1

Oct 08, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. While this particular variant has not been reported in the literature, loss-of-function variants in FLCN are known to be pathogenic (PMID: 15852235). ClinVar contains an entry for this variant (Variation ID: 230137). This sequence change creates a premature translational stop signal at codon 186 (p.Trp186*) of the FLCN gene. It is expected to result in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.66
CADD	Pathogenic	40
DANN	Uncertain	1.0
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		7.4
Vest4		0.85
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=0/200	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs876658409; hg19: chr17-17127297;