X-54446144-G-T

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 3P and 4B. PM2 PP2 BP4_Strong

The NM_004463.3(FGD1):c.2851C>A(p.Pro951Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P951S) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 23)
• Consequence: FGD1 NM_004463.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.0780

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 -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, FGD1
• BP4: Computational evidence support a benign effect (MetaRNN=0.061495036).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FGD1	NM_004463.3	c.2851C>A	p.Pro951Thr	missense_variant	18/18	ENST00000375135.4
TSR2	NM_058163.3	c.*1594G>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.2851C>A	p.Pro951Thr	missense_variant	18/18	1	NM_004463.3	P1
TSR2	ENST00000375151.5	c.*1594G>T		3_prime_UTR_variant	5/5	1	NM_058163.3	P1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 23

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

Jan 26, 2022

The c.2851C>A (p.P951T) alteration is located in exon 18 (coding exon 18) of the FGD1 gene. This alteration results from a C to A substitution at nucleotide position 2851, causing the proline (P) at amino acid position 951 to be replaced by a threonine (T). 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

Dec 16, 2023

This sequence change replaces proline, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 951 of the FGD1 protein (p.Pro951Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with FGD1-related conditions. ClinVar contains an entry for this variant (Variation ID: 2273429). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Not Available". The threonine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect 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	0.063
BayesDel_addAF	Benign	-0.21	T
BayesDel_noAF	Benign	-0.54
Cadd	Benign	16
Dann	Uncertain	1.0
DEOGEN2	Benign	0.078	T
FATHMM_MKL	Benign	0.061	N
LIST_S2	Benign	0.66	T
M_CAP	Benign	0.041	D
MetaRNN	Benign	0.061	T
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	0.55	N
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-1.1	N
REVEL	Benign	0.097
Sift	Uncertain	0.0030	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.13	B
Vest4		0.17
MutPred		0.11		Gain of phosphorylation at P951 (P = 0.0187);
MVP		0.59
MPC		2.1
ClinPred		0.79	D
GERP RS		3.4
Varity_R		0.16
gMVP		0.26

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: rs1474070705; hg19: chrX-54472577; COSMIC: COSV100911111; COSMIC: COSV100911111;