NM_000190.4:c.33+135delT
Variant names: 
Variant summary
Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.
The NM_000190.4(HMBS):c.33+135delT variant causes a intron change involving the alteration of a non-conserved nucleotide. There is a variant allele frequency bias in the population database for this variant (GnomAd4), which may indicate mosaicism or somatic mutations in the reference population data. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.
Frequency
 Genomes: 𝑓 0.0035   (  0   hom.,  cov: 0) 
 Exomes 𝑓:  0.014   (  30   hom.  ) 
Consequence
 HMBS
NM_000190.4 intron
NM_000190.4 intron
Scores
 Not classified 
Clinical Significance
 Not reported in ClinVar 
Conservation
 PhyloP100:  -0.497  
Publications
0 publications found 
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 porphyriaInheritance: 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 0 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes   AF:  0.00346  AC: 231AN: 66732Hom.:  0  Cov.: 0 show subpopulations 
GnomAD3 genomes 
 AF: 
AC: 
231
AN: 
66732
Hom.: 
Cov.: 
0
Gnomad AFR 
 AF: 
Gnomad AMI 
 AF: 
Gnomad AMR 
 AF: 
Gnomad ASJ 
 AF: 
Gnomad EAS 
 AF: 
Gnomad SAS 
 AF: 
Gnomad FIN 
 AF: 
Gnomad MID 
 AF: 
Gnomad NFE 
 AF: 
Gnomad OTH 
 AF: 
GnomAD4 exome  AF:  0.0145  AC: 10523AN: 725758Hom.:  30  Cov.: 0 AF XY:  0.0145  AC XY: 5186AN XY: 358840 show subpopulations  ⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5. 
GnomAD4 exome 
 AF: 
AC: 
10523
AN: 
725758
Hom.: 
Cov.: 
0
 AF XY: 
AC XY: 
5186
AN XY: 
358840
show subpopulations 
 ⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5. 
African (AFR) 
 AF: 
AC: 
191
AN: 
18196
American (AMR) 
 AF: 
AC: 
328
AN: 
11492
Ashkenazi Jewish (ASJ) 
 AF: 
AC: 
103
AN: 
10246
East Asian (EAS) 
 AF: 
AC: 
56
AN: 
7764
South Asian (SAS) 
 AF: 
AC: 
489
AN: 
49200
European-Finnish (FIN) 
 AF: 
AC: 
138
AN: 
11124
Middle Eastern (MID) 
 AF: 
AC: 
28
AN: 
1892
European-Non Finnish (NFE) 
 AF: 
AC: 
8809
AN: 
588564
Other (OTH) 
 AF: 
AC: 
381
AN: 
27280
 ⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals. 
 Allele Balance Distribution 
 Red line indicates average allele balance 
 Average allele balance: 0.366 
Heterozygous variant carriers
 0 
 477 
 954 
 1432 
 1909 
 2386 
 0.00 
 0.20 
 0.40 
 0.60 
 0.80 
 0.95 
Allele balance
Age Distribution
Exome Het
Exome Hom
Variant carriers
 0 
 420 
 840 
 1260 
 1680 
 2100 
 <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:  0.00350  AC: 234AN: 66768Hom.:  0  Cov.: 0 AF XY:  0.00386  AC XY: 114AN XY: 29522 show subpopulations  ⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. 
GnomAD4 genome 
 AF: 
AC: 
234
AN: 
66768
Hom.: 
Cov.: 
0
 AF XY: 
AC XY: 
114
AN XY: 
29522
show subpopulations 
 ⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. 
African (AFR) 
 AF: 
AC: 
177
AN: 
18386
American (AMR) 
 AF: 
AC: 
18
AN: 
4794
Ashkenazi Jewish (ASJ) 
 AF: 
AC: 
4
AN: 
2140
East Asian (EAS) 
 AF: 
AC: 
2
AN: 
1398
South Asian (SAS) 
 AF: 
AC: 
1
AN: 
1308
European-Finnish (FIN) 
 AF: 
AC: 
0
AN: 
1126
Middle Eastern (MID) 
 AF: 
AC: 
0
AN: 
74
European-Non Finnish (NFE) 
 AF: 
AC: 
29
AN: 
36224
Other (OTH) 
 AF: 
AC: 
2
AN: 
858
 ⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals. 
 Allele Balance Distribution 
 Red line indicates average allele balance 
 Average allele balance: 0.383 
Heterozygous variant carriers
 0 
 13 
 26 
 39 
 52 
 65 
 0.00 
 0.20 
 0.40 
 0.60 
 0.80 
 0.95 
Allele balance
Age Distribution
Genome Het
Variant carriers
 0 
 4 
 8 
 12 
 16 
 20 
 <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: 
Hom.: 
ClinVar
Not reported inComputational scores
Source: 
Name
Calibrated prediction
Score
Prediction
 PhyloP100 
Splicing
Name
Calibrated prediction
Score
Prediction
 SpliceAI score (max) 
Details are displayed if max score is > 0.2
 Find out detailed SpliceAI scores and Pangolin per-transcript scores at 
Publications
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