rs118204115

Positions:

• chr11-119092518-C-A
• chr11-119092518-C-G

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PM5 PP5

The NM_000190.4(HMBS):​c.766C>A​(p.His256Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H256Y) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: HMBS NM_000190.4 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 2.90

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.
• PP5: Variant 11-119092518-C-A is Pathogenic according to our data. Variant chr11-119092518-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 1474.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
HMBS	NM_000190.4	c.766C>A	p.His256Asn	missense_variant	11/14	ENST00000652429.1	NP_000181.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
HMBS	ENST00000652429.1	c.766C>A	p.His256Asn	missense_variant	11/14		NM_000190.4	ENSP00000498786.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Acute intermittent porphyria Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Dec 01, 1993

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Pathogenic	0.20	D
BayesDel_noAF	Uncertain	0.050
CADD	Benign	22
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.66	.;D;.;T;.;.;.;.
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Uncertain	0.95	D
M_CAP	Uncertain	0.15	D
MetaRNN	Uncertain	0.71	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.4	.;M;.;.;.;.;.;.
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-0.21	.;N;N;N;.;.;N;.
REVEL	Uncertain	0.57
Sift	Benign	0.47	.;T;T;T;.;.;T;.
Sift4G	Benign	0.37	.;T;T;T;.;.;T;.
Polyphen		0.55, 0.49	.;P;.;P;.;.;.;.
Vest4		0.57, 0.57, 0.58
MutPred		0.82		.;Gain of methylation at R255 (P = 0.2814);.;.;.;.;.;.;
MVP		0.78
MPC		0.45
ClinPred		0.72	D
GERP RS		5.2
Varity_R		0.40

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

LitVar

Other links and lift over

dbSNP: rs118204115; hg19: chr11-118963228;