rs544956641

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1PM5PP2PP3_StrongPP5_Very_Strong

The NM_000187.4(HGD):​c.365C>T​(p.Ala122Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000248 in 1,613,906 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 Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A122D) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000027 ( 0 hom. )

Consequence

HGD
NM_000187.4 missense

Scores

11
6
1

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 9.32

Publications

9 publications found
Variant links:
Genes affected
HGD (HGNC:4892): (homogentisate 1,2-dioxygenase) This gene encodes the enzyme homogentisate 1,2 dioxygenase. This enzyme is involved in the catabolism of the amino acids tyrosine and phenylalanine. Mutations in this gene are the cause of the autosomal recessive metabolism disorder alkaptonuria.[provided by RefSeq, May 2010]
HGD Gene-Disease associations (from GenCC):
  • alkaptonuria
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 17 ACMG points.

PM1
In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000187.4
PM5
Other missense variant is known to change same aminoacid residue: Variant chr3-120650843-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 2626835.Status of the report is no_assertion_criteria_provided, 0 stars.
PP2
Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 127 curated pathogenic missense variants (we use a threshold of 10). The gene has 16 curated benign missense variants. Gene score misZ: 0.28979 (below the threshold of 3.09). Trascript score misZ: 0.53625 (below the threshold of 3.09). GenCC associations: The gene is linked to alkaptonuria.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.968
PP5
Variant 3-120650843-G-A is Pathogenic according to our data. Variant chr3-120650843-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 188865.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
HGDNM_000187.4 linkc.365C>T p.Ala122Val missense_variant Exon 6 of 14 ENST00000283871.10 NP_000178.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
HGDENST00000283871.10 linkc.365C>T p.Ala122Val missense_variant Exon 6 of 14 1 NM_000187.4 ENSP00000283871.5
HGDENST00000476082.2 linkc.242C>T p.Ala81Val missense_variant Exon 5 of 7 5 ENSP00000419560.2
HGDENST00000485313.5 linkn.473C>T non_coding_transcript_exon_variant Exon 7 of 7 5
HGDENST00000492108.5 linkn.-5C>T upstream_gene_variant 2 ENSP00000419838.1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152198
Hom.:
0
Cov.:
32
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:
0.000207
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000557
AC:
14
AN:
251388
AF XY:
0.0000442
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:
0.00
Gnomad OTH exome
AF:
0.000163
GnomAD4 exome
AF:
0.0000267
AC:
39
AN:
1461590
Hom.:
0
Cov.:
31
AF XY:
0.0000344
AC XY:
25
AN XY:
727128
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33466
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26134
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39698
South Asian (SAS)
AF:
0.000429
AC:
37
AN:
86248
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53412
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111758
Other (OTH)
AF:
0.0000331
AC:
2
AN:
60382
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.469
Heterozygous variant carriers
0
3
6
10
13
16
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:
152316
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74482
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41574
American (AMR)
AF:
0.00
AC:
0
AN:
15300
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5180
South Asian (SAS)
AF:
0.000207
AC:
1
AN:
4826
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10620
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68024
Other (OTH)
AF:
0.00
AC:
0
AN:
2116
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.575
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.0000491
Hom.:
0
Bravo
AF:
0.00000756
ExAC
AF:
0.0000576
AC:
7
Asia WGS
AF:
0.000577
AC:
2
AN:
3478

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Alkaptonuria Pathogenic:7
Mar 11, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 122 of the HGD protein (p.Ala122Val). This variant is present in population databases (rs544956641, gnomAD 0.04%). This missense change has been observed in individual(s) with alkaptonuria (PMID: 12501223, 19862842, 23430897, 25804398). ClinVar contains an entry for this variant (Variation ID: 188865). 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 HGD protein function with a negative predictive value of 80%. For these reasons, this variant has been classified as Pathogenic.

Lifecell International Pvt. Ltd
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

A Homozygote Missense variant c.365C>T in Exon 6 of the HGD gene that results in the amino acid substitution p.Ala122Val was identified. The observed variant has a maximum allele frequency of 0.00006/--% in gnomAD exomes and genomes, respectively. The severity of the impact of this variant on the protein is medium, based on the effect of the protein and REVEL score . Rare Exome Variant Ensemble Learner (REVEL) is an ensembl method for predicting the pathogenicity of missense variants based on a combination of scores from 13 individual tools: MutPred, FATHMM v2.3, VEST 3.0, PolyPhen-2, SIFT, PROVEAN, MutationAssessor, MutationTaster, LRT, GERP++, SiPhy, phyloP, and phastCons. The REVEL score for an individual missense variant can range from 0 to 1, with higher scores reflecting greater likelihood that the variant is disease-causing. This variant has been reported as Pathogenic/Likely Pathogenic in the ClinVar database (Variant ID: 418295). This variant was reported among the patients for Alkaptonuria (Vilboux et al., 2009). Based on the above evidence this variant has been classified as Pathogenic according to the ACMG guidelines.

Neuberg Centre For Genomic Medicine, NCGM
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Experimental evidence suggests that this variant has 58% residual activity compared to the wild type indicating moderately tolerable variant (Lequeue S, et al., 2022). This variant shows a founder effect in Jordanian patients and is located in a mutational hot spot (Nemethova M, et al., 2016).

Department Of Human Genetics, Institute Of Clinical And Translational Research, Biomedical Research Center, Slovak Academy Of Sciences
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:research

The variant was originally described in AKU patient in PMID:12501223. It has been submitted to the HGD gene mutation database (http://hgddatabase.cvtisr.sk/, DB-ID: AKU_00031).

Aug 03, 2021
Fulgent Genetics, Fulgent Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Jul 07, 2021
Revvity Omics, Revvity
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Jul 03, 2014
Counsyl
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.51
BayesDel_addAF
Pathogenic
0.31
D
BayesDel_noAF
Pathogenic
0.53
CADD
Pathogenic
28
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.97
D;D
Eigen
Pathogenic
0.92
Eigen_PC
Pathogenic
0.91
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.96
D;D
M_CAP
Pathogenic
0.40
D
MetaRNN
Pathogenic
0.97
D;D
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Pathogenic
3.1
M;.
PhyloP100
9.3
PrimateAI
Uncertain
0.62
T
PROVEAN
Uncertain
-3.7
D;D
REVEL
Pathogenic
0.92
Sift
Benign
0.090
T;D
Sift4G
Uncertain
0.046
D;D
Vest4
0.96
ClinPred
0.86
D
GERP RS
5.9
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.88
gMVP
0.85
Mutation Taster
=21/79
disease causing (ClinVar)

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: rs544956641; hg19: chr3-120369690; API