rs1042194044

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1PM2PM5PP2PP3_Strong

The NM_003124.5(SPR):​c.523G>A​(p.Ala175Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000187 in 1,604,582 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. A175D) has been classified as Likely pathogenic.

Frequency

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

Consequence

SPR
NM_003124.5 missense

Scores

13
5
1

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 9.56

Publications

0 publications found
Variant links:
Genes affected
SPR (HGNC:11257): (sepiapterin reductase) This gene encodes an aldo-keto reductase that catalyzes the NADPH-dependent reduction of pteridine derivatives and is important in the biosynthesis of tetrahydrobiopterin (BH4). Mutations in this gene result in DOPA-responsive dystonia due to sepiaterin reductase deficiency. A pseudogene has been identified on chromosome 1. [provided by RefSeq, Jul 2008]
SPR Gene-Disease associations (from GenCC):
  • dopa-responsive dystonia due to sepiapterin reductase deficiency
    Inheritance: AD, AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, ClinGen, G2P, Ambry Genetics
  • BH4-deficient hyperphenylalaninemia A
    Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PM1
In a chain Sepiapterin reductase (size 260) in uniprot entity SPRE_HUMAN there are 9 pathogenic changes around while only 2 benign (82%) in NM_003124.5
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr2-72888533-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 807499.
PP2
Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 6 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 0.7325 (below the threshold of 3.09). Trascript score misZ: -0.70614 (below the threshold of 3.09). GenCC associations: The gene is linked to dopa-responsive dystonia due to sepiapterin reductase deficiency, BH4-deficient hyperphenylalaninemia A.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.976

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SPRNM_003124.5 linkc.523G>A p.Ala175Thr missense_variant Exon 2 of 3 ENST00000234454.6 NP_003115.1 P35270

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
SPRENST00000234454.6 linkc.523G>A p.Ala175Thr missense_variant Exon 2 of 3 1 NM_003124.5 ENSP00000234454.5 P35270
SPRENST00000498749.2 linkn.*105G>A non_coding_transcript_exon_variant Exon 2 of 3 3 ENSP00000519026.1
SPRENST00000498749.2 linkn.*105G>A 3_prime_UTR_variant Exon 2 of 3 3 ENSP00000519026.1
SPRENST00000713723.1 linkc.304+796G>A intron_variant Intron 1 of 1 ENSP00000519027.1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152220
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000241
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:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000411
AC:
1
AN:
243094
AF XY:
0.00000763
show subpopulations
Gnomad AFR exome
AF:
0.0000619
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:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000138
AC:
2
AN:
1452362
Hom.:
0
Cov.:
31
AF XY:
0.00000139
AC XY:
1
AN XY:
721380
show subpopulations
African (AFR)
AF:
0.0000602
AC:
2
AN:
33240
American (AMR)
AF:
0.00
AC:
0
AN:
43828
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
25506
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39550
South Asian (SAS)
AF:
0.00
AC:
0
AN:
84934
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53078
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5732
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1106622
Other (OTH)
AF:
0.00
AC:
0
AN:
59872
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

Age Distribution

Exome 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
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152220
Hom.:
0
Cov.:
33
AF XY:
0.00
AC XY:
0
AN XY:
74350
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000241
AC:
1
AN:
41458
American (AMR)
AF:
0.00
AC:
0
AN:
15286
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5186
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10630
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68036
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.325
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:
0.00
Hom.:
0
Bravo
AF:
0.0000113

ClinVar

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

Submissions by phenotype

Dystonic disorder Uncertain:1
Aug 24, 2017
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces alanine with threonine at codon 175 of the SPR protein (p.Ala175Thr). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and threonine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with SPR-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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
0.72
BayesDel_addAF
Pathogenic
0.34
D
BayesDel_noAF
Pathogenic
0.43
CADD
Pathogenic
32
DANN
Pathogenic
1.0
DEOGEN2
Pathogenic
0.87
D
Eigen
Pathogenic
0.89
Eigen_PC
Pathogenic
0.82
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Uncertain
0.97
D
M_CAP
Uncertain
0.28
D
MetaRNN
Pathogenic
0.98
D
MetaSVM
Pathogenic
0.97
D
MutationAssessor
Pathogenic
3.0
M
PhyloP100
9.6
PrimateAI
Uncertain
0.54
T
PROVEAN
Uncertain
-4.0
D
REVEL
Pathogenic
0.93
Sift
Pathogenic
0.0
D
Sift4G
Pathogenic
0.0
D
Polyphen
1.0
D
Vest4
0.90
MutPred
0.88
Loss of ubiquitination at K174 (P = 0.0573);
MVP
0.97
MPC
1.2
ClinPred
1.0
D
GERP RS
4.7
Varity_R
0.95
gMVP
0.90
Mutation Taster
=39/61
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
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: rs1042194044; hg19: chr2-73115661; API