rs118203972

Positions:

• chr12-32598566-C-T

Variant summary

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

The NM_001370298.3(FGD4):​c.1081C>T​(p.Arg361Ter) variant causes a stop gained change involving the alteration of a non-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)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: FGD4 NM_001370298.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3 U:1
• Conservation: PhyloP100: 2.10

Genes affected

FGD4 (HGNC:19125): (FYVE, RhoGEF and PH domain containing 4) This gene encodes a protein that is involved in the regulation of the actin cytoskeleton and cell shape. This protein contains an actin filament-binding domain, which together with its Dbl homology domain and one of its pleckstrin homology domains, can form microspikes. This protein can activate MAPK8 independently of the actin filament-binding domain, and it is also involved in the activation of CDC42 via the exchange of bound GDP for free GTP. The activation of CDC42 also enables this protein to play a role in mediating the cellular invasion of Cryptosporidium parvum, an intracellular parasite that infects the gastrointestinal tract. Mutations in this gene can cause Charcot-Marie-Tooth disease type 4H (CMT4H), a disorder of the peripheral nervous system. Multiple alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jan 2015]

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 12-32598566-C-T is Pathogenic according to our data. Variant chr12-32598566-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 1011.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr12-32598566-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FGD4	NM_001370298.3	c.1081C>T	p.Arg361Ter	stop_gained	5/17	ENST00000534526.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FGD4	ENST00000534526.7	c.1081C>T	p.Arg361Ter	stop_gained	5/17	5	NM_001370298.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1461240 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726944

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Alfa AF: 0.00152 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Uncertain:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Charcot-Marie-Tooth disease type 4H Pathogenic:1 Uncertain:1

Pathogenic, no assertion criteria provided	literature only	OMIM	Jul 01, 2007	- -
Uncertain significance, no assertion criteria provided	literature only	Inherited Neuropathy Consortium Ii, University Of Miami	Jan 06, 2016	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Oct 01, 2020

- -

Charcot-Marie-Tooth disease type 4 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 14, 2023

This sequence change creates a premature translational stop signal (p.Arg224*) in the FGD4 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in FGD4 are known to be pathogenic (PMID: 17564972). For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 1011). This premature translational stop signal has been observed in individual(s) with Charcot-Marie-Tooth disease (PMID: 17564972). This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	39
DANN	Uncertain	1.0
Eigen	Pathogenic	0.72
Eigen_PC	Uncertain	0.56
FATHMM_MKL	Uncertain	0.91	D
MutationTaster	Benign	1.0	A;A;A;A;A;A;A
Vest4		0.95
GERP RS		4.0

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: rs118203972; hg19: chr12-32751500; COSMIC: COSV56781132;