chr16-74774662-G-C

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PM2

The NM_024306.5(FA2H):c.94C>G(p.Arg32Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000348 in 1,437,934 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. R32R) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000033 ( 0 hom. )

Consequence

FA2H
NM_024306.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:4

Conservation

PhyloP100: 1.56

Publications

0 publications found

Variant links:

Genes affected

FA2H (HGNC:21197): (fatty acid 2-hydroxylase) This gene encodes a protein that catalyzes the synthesis of 2-hydroxysphingolipids, a subset of sphingolipids that contain 2-hydroxy fatty acids. Sphingolipids play roles in many cellular processes and their structural diversity arises from modification of the hydrophobic ceramide moiety, such as by 2-hydroxylation of the N-acyl chain, and the existence of many different head groups. Mutations in this gene have been associated with leukodystrophy dysmyelinating with spastic paraparesis with or without dystonia.[provided by RefSeq, Mar 2010]

FA2H Gene-Disease associations (from GenCC):

hereditary spastic paraplegia 35
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae), G2P

FA2H links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_024306.5

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FA2H	NM_024306.5 link	c.94C>G	p.Arg32Gly	missense_variant	Exon 1 of 7	ENST00000219368.8	NP_077282.3	Q7L5A8-1
FA2H	XM_011523317.4 link	c.94C>G	p.Arg32Gly	missense_variant	Exon 1 of 6		XP_011521619.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FA2H	ENST00000219368.8 link	c.94C>G	p.Arg32Gly	missense_variant	Exon 1 of 7	1	NM_024306.5	ENSP00000219368.3		Q7L5A8-1
FA2H	ENST00000567683.5 link	n.94C>G		non_coding_transcript_exon_variant	Exon 1 of 5	2		ENSP00000455126.1		H3BP32

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152084

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:

0.000103

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000293

AC:

AN:

68276

AF XY:

0.0000502

show subpopulations

Gnomad AFR exome

AF:

0.00

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:

0.0000778

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000334

AC:

AN:

1285850

Hom.:

Cov.:

AF XY:

0.0000316

AC XY:

AN XY:

632382

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

26388

American (AMR)

AF:

0.00

AC:

AN:

23610

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

22352

East Asian (EAS)

AF:

0.00

AC:

AN:

27860

South Asian (SAS)

AF:

0.00

AC:

AN:

65334

European-Finnish (FIN)

AF:

0.00

AC:

AN:

32414

Middle Eastern (MID)

AF:

0.00

AC:

AN:

3864

European-Non Finnish (NFE)

AF:

0.0000407

AC:

AN:

1030844

Other (OTH)

AF:

0.0000188

AC:

AN:

53184

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.504

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152084

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74298

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41458

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5176

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10578

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.000103

AC:

AN:

67976

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.454

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000264

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Nov 07, 2024

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 24359114, 32624042) -

not specified

Uncertain:1

May 22, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: FA2H c.94C>G (p.Arg32Gly) results in a non-conservative amino acid change located in the Cytochrome b5-like heme/steroid binding domain (IPR001199) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 2.9e-05 in 68276 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.94C>G has been reported in the literature in the compound heterozygous state in an individual affected with Neurodegeneration without significant white matter lesions or brain iron accumulation (Leal Ferman_2020). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 32624042). ClinVar contains an entry for this variant (Variation ID: 406878). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Spastic paraplegia

Uncertain:1

Dec 04, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 32 of the FA2H protein (p.Arg32Gly). This variant is present in population databases (no rsID available, gnomAD 0.007%). This missense change has been observed in individual(s) with clinical features of FA2H-related conditions (PMID: 32624042; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 406878). 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) performed at Invitae indicates that this missense variant is not expected to disrupt FA2H protein function with a negative predictive value of 80%. 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. -

Hereditary spastic paraplegia 35

Uncertain:1

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Hereditary spastic paraplegia

Uncertain:1

Jul 15, 2020

Genome Diagnostics Laboratory, The Hospital for Sick Children

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.21

BayesDel_addAF

Benign

-0.064

BayesDel_noAF

Benign

-0.14

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.64

Eigen

Benign

-0.033

Eigen_PC

Benign

-0.046

FATHMM_MKL

Benign

0.53

LIST_S2

Benign

0.71

M_CAP

Pathogenic

0.97

MetaRNN

Uncertain

0.57

MetaSVM

Benign

-0.60

MutationAssessor

Benign

1.4

PhyloP100

1.6

PrimateAI

Pathogenic

0.94

PROVEAN

Uncertain

-2.6

REVEL

Uncertain

0.53

Sift

Benign

0.17

Sift4G

Benign

0.28

Polyphen

0.84

Vest4

0.45

MutPred

0.58

Loss of MoRF binding (P = 0.0173);

MVP

0.22

MPC

2.0

ClinPred

0.53

GERP RS

1.9

PromoterAI

0.072

Neutral

(source)

Varity_R

0.38

gMVP

0.86

Mutation Taster

=72/28

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over