chr12-32624993-C-G

Variant names:

• chr12-32624993-C-G
• rs61748364
• NM_001370298.3:c.1971C>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001370298.3(FGD4):​c.1971C>G​(p.Ile657Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000682 in 1,613,136 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. I657I) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: FGD4 NM_001370298.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.0640
• Publications: 5 publications found

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]

FGD4 Gene-Disease associations (from GenCC):

• Charcot-Marie-Tooth disease

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• Charcot-Marie-Tooth disease type 4H

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FGD4	NM_001370298.3	c.1971C>G	p.Ile657Met	missense_variant	Exon 13 of 17	ENST00000534526.7	NP_001357227.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FGD4	ENST00000534526.7	c.1971C>G	p.Ile657Met	missense_variant	Exon 13 of 17	5	NM_001370298.3	ENSP00000449273.1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152162 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000724

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000119 AC: 3 AN: 251410 AF XY: 0.00000736

Gnomad AFR exome AF: 0.000123

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000548 AC: 8 AN: 1460856 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 726744

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.000149 AC: 5 AN: 33448

American (AMR) AF: 0.00 AC: 0 AN: 44708

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26100

East Asian (EAS) AF: 0.00 AC: 0 AN: 39596

South Asian (SAS) AF: 0.00 AC: 0 AN: 86208

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53324

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111390

Other (OTH) AF: 0.00 AC: 0 AN: 60324

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000812205), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152280 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74468

African (AFR) AF: 0.0000722 AC: 3 AN: 41550

American (AMR) AF: 0.00 AC: 0 AN: 15290

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5184

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10610

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2116

Alfa AF: 0.00 Hom.: 2

Bravo AF: 0.00000378

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.047	T
BayesDel_noAF	Uncertain	-0.070
CADD	Benign	20
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.57	D;D;D;D;D
Eigen	Benign	0.079
Eigen_PC	Benign	-0.013
FATHMM_MKL	Uncertain	0.76	D
LIST_S2	Uncertain	0.91	D;D;D;D;D
M_CAP	Benign	0.055	D
MetaRNN	Uncertain	0.72	D;D;D;D;D
MetaSVM	Uncertain	-0.27	T
MutationAssessor	Uncertain	2.3	.;.;M;.;.
PhyloP100		-0.064
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-2.0	N;N;N;N;N
REVEL	Uncertain	0.55
Sift	Benign	0.070	T;T;T;T;T
Sift4G	Uncertain	0.0020	D;D;D;D;D
Polyphen		0.96, 0.99, 0.98	.;D;D;.;D
Vest4		0.76
MutPred		0.62		.;.;.;.;Gain of disorder (P = 0.0592);
MVP		0.74
MPC		0.90
ClinPred		0.80	D
GERP RS		-0.49
Varity_R		0.11
gMVP		0.83
Mutation Taster		=48/52	disease causing

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: rs61748364; hg19: chr12-32777927;