NM_006859.4:c.218G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_006859.4(LIAS):​c.218G>C​(p.Arg73Thr) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000019 in 1,581,418 control chromosomes in the GnomAD database, with no homozygous occurrence. 2/3 splice prediction tools predicting alterations to normal splicing. 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. R73G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

LIAS
NM_006859.4 missense, splice_region

Scores

6
10
3
Splicing: ADA: 1.000
2

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 9.06

Publications

0 publications found
Variant links:
Genes affected
LIAS (HGNC:16429): (lipoic acid synthetase) The protein encoded by this gene belongs to the biotin and lipoic acid synthetases family. Localized in the mitochondrion, this iron-sulfur enzyme catalyzes the final step in the de novo pathway for the biosynthesis of lipoic acid, a potent antioxidant. The deficient expression of this enzyme has been linked to conditions such as diabetes, atherosclerosis and neonatal-onset epilepsy. Alternative splicing occurs at this locus, and several transcript variants encoding distinct isoforms have been identified. [provided by RefSeq, Aug 2020]
LIAS Gene-Disease associations (from GenCC):
  • lipoic acid synthetase deficiency
    Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P
  • Leigh syndrome
    Inheritance: AR Classification: LIMITED Submitted by: ClinGen

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
LIASNM_006859.4 linkc.218G>C p.Arg73Thr missense_variant, splice_region_variant Exon 2 of 11 ENST00000640888.2 NP_006850.2 O43766-1A0A024R9W0

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
LIASENST00000640888.2 linkc.218G>C p.Arg73Thr missense_variant, splice_region_variant Exon 2 of 11 1 NM_006859.4 ENSP00000492260.1 O43766-1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152142
Hom.:
0
Cov.:
33
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:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD4 exome
AF:
0.00000140
AC:
2
AN:
1429276
Hom.:
0
Cov.:
30
AF XY:
0.00000141
AC XY:
1
AN XY:
708774
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
31750
American (AMR)
AF:
0.00
AC:
0
AN:
37808
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
24884
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39294
South Asian (SAS)
AF:
0.00
AC:
0
AN:
80300
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52748
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5632
European-Non Finnish (NFE)
AF:
0.00000182
AC:
2
AN:
1097938
Other (OTH)
AF:
0.00
AC:
0
AN:
58922
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.450
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152142
Hom.:
0
Cov.:
33
AF XY:
0.0000135
AC XY:
1
AN XY:
74304
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41424
American (AMR)
AF:
0.00
AC:
0
AN:
15280
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5200
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10588
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68034
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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:
0.0000564
Hom.:
0
Bravo
AF:
0.00000378

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Lipoic acid synthetase deficiency Uncertain:1
Oct 24, 2024
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 threonine, which is neutral and polar, at codon 73 of the LIAS protein (p.Arg73Thr). This variant also falls at the last nucleotide of exon 2, which is part of the consensus splice site for this exon. This variant is present in population databases (no rsID available, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with LIAS-related conditions. ClinVar contains an entry for this variant (Variation ID: 472878). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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
Pathogenic
0.91
BayesDel_addAF
Pathogenic
0.23
D
BayesDel_noAF
Uncertain
0.090
CADD
Pathogenic
35
DANN
Uncertain
0.98
DEOGEN2
Uncertain
0.78
D;T;T;.;T;.;.;.;.
Eigen
Pathogenic
0.69
Eigen_PC
Pathogenic
0.77
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.97
D;T;D;D;D;T;D;T;D
M_CAP
Uncertain
0.11
D
MetaRNN
Uncertain
0.59
D;D;D;D;D;D;D;D;D
MetaSVM
Uncertain
-0.054
T
MutationAssessor
Uncertain
2.3
M;.;.;M;.;.;M;.;.
PhyloP100
9.1
PrimateAI
Uncertain
0.76
T
PROVEAN
Pathogenic
-4.8
.;.;.;D;N;D;D;.;.
REVEL
Uncertain
0.55
Sift
Benign
0.13
.;.;.;T;T;T;T;.;.
Sift4G
Benign
0.18
.;.;.;T;T;T;T;.;.
Polyphen
0.99
D;D;D;.;D;.;.;.;.
Vest4
0.73, 0.80, 0.75, 0.76
MutPred
0.42
Gain of phosphorylation at R73 (P = 0.044);Gain of phosphorylation at R73 (P = 0.044);Gain of phosphorylation at R73 (P = 0.044);Gain of phosphorylation at R73 (P = 0.044);Gain of phosphorylation at R73 (P = 0.044);Gain of phosphorylation at R73 (P = 0.044);Gain of phosphorylation at R73 (P = 0.044);Gain of phosphorylation at R73 (P = 0.044);Gain of phosphorylation at R73 (P = 0.044);
MVP
0.86
MPC
0.79
ClinPred
0.97
D
GERP RS
6.1
Varity_R
0.58
gMVP
0.80
Mutation Taster
=16/84
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
1.0
SpliceAI score (max)
0.020
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs1172950083; hg19: chr4-39462582; API