Genetic Variant FDFT1:c.100-101G>A (chr8-11808693-G-A) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001287750.2(FDFT1):c.176G>A(p.Trp59*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000408 in 1,471,840 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000015 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000030 ( 0 hom. )

Consequence

FDFT1
NM_001287750.2 stop_gained

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.800

Variant links:

Genes affected

FDFT1 (HGNC:3629): (farnesyl-diphosphate farnesyltransferase 1) This gene encodes a membrane-associated enzyme located at a branch point in the mevalonate pathway. The encoded protein is the first specific enzyme in cholesterol biosynthesis, catalyzing the dimerization of two molecules of farnesyl diphosphate in a two-step reaction to form squalene. [provided by RefSeq, Jul 2008]

FDFT1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 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
FDFT1	NM_004462.5 link	c.100-101G>A		intron_variant	Intron 1 of 7	ENST00000220584.9	NP_004453.3	P37268-1Q6IAX1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FDFT1	ENST00000220584.9 link	c.100-101G>A		intron_variant	Intron 1 of 7	1	NM_004462.5	ENSP00000220584.4		P37268-1

Frequencies

GnomAD3 genomes

AF:

0.0000145

AC:

AN:

137548

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000318

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000300

AC:

AN:

1334292

Hom.:

Cov.:

AF XY:

0.00000153

AC XY:

AN XY:

654734

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000284

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000287

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000145

AC:

AN:

137548

Hom.:

Cov.:

AF XY:

0.0000150

AC XY:

AN XY:

66658

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000318

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Squalene synthase deficiency

Uncertain:1

Feb 02, 2022

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as VUS-3C. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with squalene synthase deficiency (MIM#618156). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0202 - Variant is predicted to cause nonsense-mediated decay (NMD) and loss of protein (premature termination codon is located at least 54 nucleotides upstream of the final exon-exon junction), but is located in an exon that may undergo alternative splicing. (I) 0219 - This variant is non-coding in an alternative transcript. This variant is either intronic or in the 5' UTR of all other isoforms of this gene, including the predominant transcript used in ClinVar (UCSC). (I) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD (v3) <0.01 for a recessive condition (2 heterozygotes, 0 homozygotes). (SP) 0705 - No comparable NMD-predicted variants in this transcript have previous evidence for pathogenicity. (I) 0807 - This variant has no previous evidence of pathogenicity. (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.81

CADD

Benign

DANN

Benign

0.88

FATHMM_MKL

Benign

0.062

GERP RS

-3.6

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over