4-17501790-G-T

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1PM2PP2PP3_Moderate

The NM_000320.3(QDPR):​c.365C>A​(p.Ala122Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,868 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 (★).

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

QDPR
NM_000320.3 missense

Scores

11
7
1

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 9.10

Publications

0 publications found
Variant links:
Genes affected
QDPR (HGNC:9752): (quinoid dihydropteridine reductase) This gene encodes the enzyme dihydropteridine reductase, which catalyzes the NADH-mediated reduction of quinonoid dihydrobiopterin. This enzyme is an essential component of the pterin-dependent aromatic amino acid hydroxylating systems. Mutations in this gene resulting in QDPR deficiency include aberrant splicing, amino acid substitutions, insertions, or premature terminations. Dihydropteridine reductase deficiency presents as atypical phenylketonuria due to insufficient production of biopterin, a cofactor for phenylalanine hydroxylase. [provided by RefSeq, Jul 2008]
QDPR Gene-Disease associations (from GenCC):
  • dihydropteridine reductase deficiency
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, G2P, Orphanet, Labcorp Genetics (formerly Invitae)

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

PM1
In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000320.3
PM2
Very rare variant in population databases, with high coverage;
PP2
Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 24 curated pathogenic missense variants (we use a threshold of 10). The gene has 7 curated benign missense variants. Gene score misZ: 0.28456 (below the threshold of 3.09). Trascript score misZ: 0.32173 (below the threshold of 3.09). GenCC associations: The gene is linked to dihydropteridine reductase deficiency.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.868

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
QDPRNM_000320.3 linkc.365C>A p.Ala122Asp missense_variant Exon 4 of 7 ENST00000281243.10 NP_000311.2 P09417-1A0A140VKA9
QDPRNM_001306140.2 linkc.272C>A p.Ala91Asp missense_variant Exon 3 of 6 NP_001293069.1 P09417-2
QDPRNR_156494.2 linkn.401C>A non_coding_transcript_exon_variant Exon 4 of 6

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
QDPRENST00000281243.10 linkc.365C>A p.Ala122Asp missense_variant Exon 4 of 7 1 NM_000320.3 ENSP00000281243.5 P09417-1

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD4 exome
AF:
6.84e-7
AC:
1
AN:
1461868
Hom.:
0
Cov.:
35
AF XY:
0.00
AC XY:
0
AN XY:
727236
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53416
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111992
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
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
Cov.:
33
Alfa
AF:
0.00
Hom.:
0

ClinVar

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

Submissions by phenotype

Dihydropteridine reductase deficiency Uncertain:1
Aug 31, 2021
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces alanine with aspartic acid at codon 122 of the QDPR protein (p.Ala122Asp). The alanine residue is highly conserved and there is a moderate physicochemical difference between alanine and aspartic acid. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with QDPR-related conditions. 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. 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
0.99
BayesDel_addAF
Pathogenic
0.56
D
BayesDel_noAF
Pathogenic
0.57
CADD
Pathogenic
29
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.44
T;D;.;.
Eigen
Pathogenic
0.68
Eigen_PC
Pathogenic
0.71
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.97
.;D;D;D
M_CAP
Uncertain
0.18
D
MetaRNN
Pathogenic
0.87
D;D;D;D
MetaSVM
Uncertain
0.37
D
MutationAssessor
Pathogenic
3.5
.;H;.;.
PhyloP100
9.1
PrimateAI
Uncertain
0.74
T
PROVEAN
Pathogenic
-5.3
D;D;D;D
REVEL
Pathogenic
0.92
Sift
Uncertain
0.0010
D;D;D;D
Sift4G
Pathogenic
0.0010
D;D;D;D
Polyphen
1.0
.;D;.;.
Vest4
0.97
MutPred
0.57
Gain of disorder (P = 0.0633);Gain of disorder (P = 0.0633);.;Gain of disorder (P = 0.0633);
MVP
0.99
MPC
0.92
ClinPred
1.0
D
GERP RS
5.7
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.99
gMVP
0.99
Mutation Taster
=1/99
disease causing

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

Other links and lift over

dbSNP: rs1553875105; hg19: chr4-17503413; API