11-119085055-G-A

Variant summary

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

The NM_000190.4(HMBS):c.22G>A(p.Ala8Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: HMBS NM_000190.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.790

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=0.21779597).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
HMBS	NM_000190.4	c.22G>A	p.Ala8Thr	missense_variant	1/14	ENST00000652429.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
HMBS	ENST00000652429.1	c.22G>A	p.Ala8Thr	missense_variant	1/14		NM_000190.4	P3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 43

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 15, 2021

The c.22G>A (p.A8T) alteration is located in exon 1 (coding exon 1) of the HMBS gene. This alteration results from a G to A substitution at nucleotide position 22, causing the alanine (A) at amino acid position 8 to be replaced by a threonine (T). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.088
BayesDel_addAF	Uncertain	0.075	D
BayesDel_noAF	Benign	-0.13
Cadd	Benign	16
Dann	Benign	0.97
Eigen	Benign	-0.68
Eigen_PC	Benign	-0.61
FATHMM_MKL	Benign	0.44	N
M_CAP	Pathogenic	0.75	D
MetaRNN	Benign	0.22	T;T;T;T;T
MetaSVM	Pathogenic	1.2	D
MutationTaster	Benign	1.0	D;D;D;N;N;N
PrimateAI	Benign	0.35	T
Polyphen		0.083, 0.24	.;B;.;.;B
Vest4		0.22, 0.19, 0.26
MutPred		0.29		Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);Loss of helix (P = 0.0068);
MVP		0.61
MPC		0.67
ClinPred		0.54	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.060

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr11-118955765;