11-119092958-G-C

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2PP3

The NM_000190.4(HMBS):​c.849G>C​(p.Trp283Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000031 in 1,614,054 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: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

HMBS
NM_000190.4 missense

Scores

9
5
3

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 4.97

Publications

14 publications found
Variant links:
Genes affected
HMBS (HGNC:4982): (hydroxymethylbilane synthase) This gene encodes a member of the hydroxymethylbilane synthase superfamily. The encoded protein is the third enzyme of the heme biosynthetic pathway and catalyzes the head to tail condensation of four porphobilinogen molecules into the linear hydroxymethylbilane. Mutations in this gene are associated with the autosomal dominant disease acute intermittent porphyria. Alternatively spliced transcript variants encoding different isoforms have been described. [provided by RefSeq, Jul 2008]
HMBS Gene-Disease associations (from GenCC):
  • acute intermittent porphyria
    Inheritance: SD, AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PP3
MetaRNN computational evidence supports a deleterious effect, 0.824

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000190.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
HMBS
NM_000190.4
MANE Select
c.849G>Cp.Trp283Cys
missense
Exon 13 of 14NP_000181.2
HMBS
NM_001425056.1
c.840G>Cp.Trp280Cys
missense
Exon 13 of 14NP_001411985.1
HMBS
NM_001425057.1
c.831G>Cp.Trp277Cys
missense
Exon 13 of 14NP_001411986.1

Ensembl Transcripts

Selected
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
HMBS
ENST00000652429.1
MANE Select
c.849G>Cp.Trp283Cys
missense
Exon 13 of 14ENSP00000498786.1
HMBS
ENST00000392841.1
TSL:1
c.798G>Cp.Trp266Cys
missense
Exon 13 of 14ENSP00000376584.1
HMBS
ENST00000442944.7
TSL:5
c.831G>Cp.Trp277Cys
missense
Exon 13 of 14ENSP00000392041.3

Frequencies

GnomAD3 genomes
AF:
0.0000131
AC:
2
AN:
152182
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000131
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:
0.0000119
AC:
3
AN:
251494
AF XY:
0.00
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000867
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:
0.00000205
AC:
3
AN:
1461872
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
727234
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.0000671
AC:
3
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:
86254
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111996
Other (OTH)
AF:
0.00
AC:
0
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.492
Heterozygous variant carriers
0
1
1
2
2
3
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:
0.0000131
AC:
2
AN:
152182
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74338
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41444
American (AMR)
AF:
0.000131
AC:
2
AN:
15284
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5198
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10616
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68020
Other (OTH)
AF:
0.00
AC:
0
AN:
2088
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.600
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:
0.00
Hom.:
0

ClinVar

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

Submissions by phenotype

not provided Uncertain:1
Nov 24, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

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. 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 HMBS protein function. This variant has not been reported in the literature in individuals affected with HMBS-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.01%). This sequence change replaces tryptophan, which is neutral and slightly polar, with cysteine, which is neutral and slightly polar, at codon 283 of the HMBS protein (p.Trp283Cys).

Computational scores

Source: dbNSFP v4.9

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.89
BayesDel_addAF
Pathogenic
0.17
D
BayesDel_noAF
Pathogenic
0.20
CADD
Pathogenic
30
DANN
Uncertain
0.99
DEOGEN2
Pathogenic
0.91
D
Eigen
Uncertain
0.54
Eigen_PC
Uncertain
0.59
FATHMM_MKL
Uncertain
0.90
D
M_CAP
Pathogenic
0.34
D
MetaRNN
Pathogenic
0.82
D
MetaSVM
Pathogenic
0.93
D
MutationAssessor
Benign
0.65
N
PhyloP100
5.0
PrimateAI
Uncertain
0.59
T
PROVEAN
Pathogenic
-4.6
D
REVEL
Pathogenic
0.80
Sift
Benign
0.18
T
Sift4G
Benign
0.17
T
Polyphen
0.99
D
Vest4
0.56
MutPred
0.76
Gain of disorder (P = 0.137)
MVP
0.76
MPC
1.4
ClinPred
0.91
D
GERP RS
5.2
RBP_binding_hub_radar
1.1
RBP_regulation_power_radar
2.8
Varity_R
0.87
Mutation Taster
=38/62
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: rs118204117; hg19: chr11-118963668; API