11-119085053-C-T

Variant names:

• chr11-119085053-C-T
• NM_000190.4:c.20C>T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000190.4(HMBS):​c.20C>T​(p.Ala7Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,296 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: HMBS NM_000190.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.353

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.13007915).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
HMBS	NM_000190.4	c.20C>T	p.Ala7Val	missense_variant	Exon 1 of 14	ENST00000652429.1	NP_000181.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
HMBS	ENST00000652429.1	c.20C>T	p.Ala7Val	missense_variant	Exon 1 of 14		NM_000190.4	ENSP00000498786.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461296 Hom.: 0 Cov.: 43 AF XY: 0.00000138 AC XY: 1 AN XY: 726958

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Aug 09, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

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 7 of the HMBS protein (p.Ala7Val). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with HMBS-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests 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	Benign	0.11
BayesDel_addAF	Uncertain	0.12	D
BayesDel_noAF	Uncertain	-0.070
CADD	Benign	18
DANN	Uncertain	0.98
DEOGEN2	Benign	0.30	.;T;T;.;T
Eigen	Benign	-0.95
Eigen_PC	Benign	-0.93
FATHMM_MKL	Benign	0.27	N
M_CAP	Pathogenic	0.30	D
MetaRNN	Benign	0.13	T;T;T;T;T
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Benign	1.4	.;L;.;L;.
PrimateAI	Benign	0.34	T
PROVEAN	Benign	-0.16	.;N;N;N;N
REVEL	Uncertain	0.40
Sift	Benign	0.050	.;D;D;T;D
Sift4G	Benign	0.16	.;T;T;T;T
Polyphen		0.0	.;B;.;.;B
Vest4		0.17, 0.20, 0.25
MutPred		0.29		Loss of helix (P = 0.0033);Loss of helix (P = 0.0033);Loss of helix (P = 0.0033);Loss of helix (P = 0.0033);Loss of helix (P = 0.0033);
MVP		0.84
MPC		0.69
ClinPred		0.84	D
GERP RS		-0.21
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0
Varity_R		0.057

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr11-118955763;