3-120650843-G-T

Variant names:

• chr3-120650843-G-T
• rs544956641
• NM_000187.4:c.365C>A
• HGD p.Ala122Asp

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5

The NM_000187.4(HGD):​c.365C>A​(p.Ala122Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 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. A122V) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: HGD NM_000187.4 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 9.32
• Publications: 2 publications found

Genes affected

HGD (HGNC:4892): (homogentisate 1,2-dioxygenase) This gene encodes the enzyme homogentisate 1,2 dioxygenase. This enzyme is involved in the catabolism of the amino acids tyrosine and phenylalanine. Mutations in this gene are the cause of the autosomal recessive metabolism disorder alkaptonuria.[provided by RefSeq, May 2010]

HGD Gene-Disease associations (from GenCC):

• alkaptonuria

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 5 uncertain in NM_000187.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-120650843-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 188865.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 127 curated pathogenic missense variants (we use a threshold of 10). The gene has 16 curated benign missense variants. Gene score misZ: 0.28979 (below the threshold of 3.09). Trascript score misZ: 0.53625 (below the threshold of 3.09). GenCC associations: The gene is linked to alkaptonuria.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.983
• PP5: Variant 3-120650843-G-T is Pathogenic according to our data. Variant chr3-120650843-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 2626835.Status of the report is no_assertion_criteria_provided, 0 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000187.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HGD	NM_000187.4	MANE Select	c.365C>A	p.Ala122Asp	missense	Exon 6 of 14	NP_000178.2	Q93099

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HGD	ENST00000283871.10	TSL:1 MANE Select	c.365C>A	p.Ala122Asp	missense	Exon 6 of 14	ENSP00000283871.5	Q93099
	HGD	ENST00000898838.1		c.365C>A	p.Ala122Asp	missense	Exon 6 of 15	ENSP00000568897.1
	HGD	ENST00000898833.1		c.365C>A	p.Ala122Asp	missense	Exon 6 of 14	ENSP00000568892.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Alkaptonuria (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.87
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.98	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.5	M
PhyloP100		9.3
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-5.3	D
REVEL	Pathogenic	0.95
Sift	Benign	0.14	T
Sift4G	Uncertain	0.043	D
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.98
gMVP		0.94
Mutation Taster		=1/99	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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs544956641;

hg19: chr3-120369690;