X-54446138-C-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 1P and 6B. PP2 BP4_Moderate BS2

The NM_004463.3(FGD1):c.2857G>A(p.Glu953Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000082 in 1,097,132 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 5 hemizygotes in GnomAD. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 22)
  • Exomes 𝑓: 0.0000082 (0 hom. 5 hem.)
• Consequence: FGD1 NM_004463.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.42

Genes affected

FGD1 (HGNC:3663): (FYVE, RhoGEF and PH domain containing 1) This gene encodes a protein that contains Dbl (DH) and pleckstrin (PH) homology domains and is similar to the Rho family of small GTP-binding proteins. The encoded protein specifically binds to the Rho family GTPase Cdc42Hs and can stimulate the GDP-GTP exchange of the isoprenylated form of Cdc42Hs. It also stimulates the mitogen activated protein kinase cascade leading to c-Jun kinase SAPK/JNK1 activation. Defects in this gene are the cause of the faciogenital dysplasia in Aarskog-Scott syndrome and a syndromatic form of X-linked cognitive disability. [provided by RefSeq, Jul 2017]

TSR2 (HGNC:25455): (TSR2 ribosome maturation factor) The protein encoded by this gene appears to repress the transcription of NF-kappaB and may be involved in apoptosis. Defects in this gene are a cause of Diamond-Blackfan anemia. [provided by RefSeq, Oct 2016]

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• PP2: Missense variant where missense usually causes diseases, FGD1
• BP4: Computational evidence support a benign effect (MetaRNN=0.102986455).
• BS2: High Hemizygotes in GnomAdExome at 2 XL gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FGD1	NM_004463.3	c.2857G>A	p.Glu953Lys	missense_variant	18/18	ENST00000375135.4
TSR2	NM_058163.3	c.*1588C>T		3_prime_UTR_variant	5/5	ENST00000375151.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FGD1	ENST00000375135.4	c.2857G>A	p.Glu953Lys	missense_variant	18/18	1	NM_004463.3	P1
TSR2	ENST00000375151.5	c.*1588C>T		3_prime_UTR_variant	5/5	1	NM_058163.3	P1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD3 exomes AF: 0.0000168 AC: 3 AN: 178589 Hom.: 0 AF XY: 0.0000310 AC XY: 2 AN XY: 64517

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000740

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000540

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000820 AC: 9 AN: 1097132 Hom.: 0 Cov.: 30 AF XY: 0.0000138 AC XY: 5 AN XY: 362552

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000570

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000556

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000356

Gnomad4 OTH exome AF: 0.0000217

GnomAD4 genome Cov.: 22

Bravo AF: 0.0000264

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 02, 2023

The c.2857G>A (p.E953K) alteration is located in exon 18 (coding exon 18) of the FGD1 gene. This alteration results from a G to A substitution at nucleotide position 2857, causing the glutamic acid (E) at amino acid position 953 to be replaced by a lysine (K). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 27, 2023

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 953 of the FGD1 protein (p.Glu953Lys). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with FGD1-related conditions. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on FGD1 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.090
BayesDel_addAF	Benign	-0.12	T
BayesDel_noAF	Benign	-0.41
Cadd	Benign	17
Dann	Uncertain	1.0
DEOGEN2	Benign	0.077	T
FATHMM_MKL	Benign	0.22	N
LIST_S2	Benign	0.77	T
M_CAP	Benign	0.032	D
MetaRNN	Benign	0.10	T
MetaSVM	Benign	-0.94	T
MutationAssessor	Benign	0.69	N
MutationTaster	Benign	1.0	N
PrimateAI	Uncertain	0.51	T
PROVEAN	Benign	-0.63	N
REVEL	Benign	0.16
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.33	B
Vest4		0.076
MVP		0.61
MPC		1.7
ClinPred		0.27	T
GERP RS		5.0
Varity_R		0.45
gMVP		0.48

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: rs781589438; hg19: chrX-54472571;