rs776896550

Variant names:

• chr17-17226224-C-CT
• rs776896550
• NM_144997.7:c.347dupA

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_144997.7(FLCN):​c.347dupA​(p.Leu117AlafsTer16) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,862 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: FLCN NM_144997.7 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 7.65

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 Pathogenic. Variant got 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 17-17226224-C-CT is Pathogenic according to our data. Variant chr17-17226224-C-CT is described in ClinVar as [Pathogenic]. Clinvar id is 241922.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.347dupA	p.Leu117AlafsTer16	frameshift_variant	Exon 5 of 14	ENST00000285071.9	NP_659434.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FLCN	ENST00000285071.9	c.347dupA	p.Leu117AlafsTer16	frameshift_variant	Exon 5 of 14	1	NM_144997.7	ENSP00000285071.4
ENSG00000264187	ENST00000427497.3	n.148+1765dupA		intron_variant	Intron 4 of 11	1		ENSP00000394249.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251348 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135882

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461862 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727224

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: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Birt-Hogg-Dube syndrome 1 Pathogenic:1

Jan 10, 2024

Myriad Genetics, Inc.

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered pathogenic. This variant creates a frameshift predicted to result in premature protein truncation. -

not provided Pathogenic:1

Mar 08, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Identified in patients with Birt-Hogg-Dub syndrome in published literature (Toro et al., 2008; Palmirotta et al., 2008; Maff et al., 2011; Pradella et al., 2013); This variant is associated with the following publications: (PMID: 21937013, 23386036, 18234728, 20618353, 18573707, 29357828, 24307375) -

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

Feb 07, 2024

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome Pathogenic:1

Sep 05, 2022

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.347dupA pathogenic mutation, located in coding exon 2 of the FLCN gene, results from a duplication of A at nucleotide position 347, causing a translational frameshift with a predicted alternate stop codon (p.L117Afs*16). This alteration has been reported in multiple individuals meeting clinical diagnostic criteria for Birt-Hogg-Dube syndrome (Toro JR et al. J. Med. Genet. 2008 Jun;45:321-31; Maffé A et al. Clin. Genet. 2011 Apr;79:345-54; Pradella LM et al. Eur. J. Hum. Genet. 2013 Oct;21:1169-72). Of note, this alteration is also known as c.802insA and c.802dupA in published literature. In addition to the clinical data presented in the literature, 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

Aug 21, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Leu117Alafs*16) in the FLCN gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in FLCN are known to be pathogenic (PMID: 15852235). This variant is present in population databases (rs776896550, gnomAD 0.0009%). This premature translational stop signal has been observed in individual(s) with skin fibrofolliculomas, lung cysts, and pneumothorax consistent with Birt-Hogg-Dubé syndrome (PMID: 18234728, 20618353, 23386036). It has also been observed to segregate with disease in related individuals. This variant is also known as 802insA or 802dupA. ClinVar contains an entry for this variant (Variation ID: 241922). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

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: rs776896550; hg19: chr17-17129538;