rs72558463

Variant names:

• chrX-38411898-C-G
• NM_000531.6:c.904C>G

Your query was ambiguous. Multiple possible variants found:

• chrX-38411898-C-G
• chrX-38411898-C-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_000531.6(OTC):​c.904C>G​(p.His302Asp) 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H302L) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 23)
• Consequence: OTC NM_000531.6 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.45

Genes affected

OTC (HGNC:8512): (ornithine transcarbamylase) This nuclear gene encodes a mitochondrial matrix enzyme. The encoded protein is involved in the urea cycle which functions to detoxify ammonia into urea for excretion. Mutations in this enzyme lead to ornithine transcarbamylase deficiency, which causes hyperammonemia. [provided by RefSeq, May 2022]

ENSG00000250349 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM1: In a strand (size 3) in uniprot entity OTC_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_000531.6
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.996
• PP5: Variant X-38411898-C-G is Pathogenic according to our data. Variant chrX-38411898-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1501921.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
OTC	NM_000531.6	c.904C>G	p.His302Asp	missense_variant	Exon 9 of 10	ENST00000039007.5	NP_000522.3
OTC	NM_001407092.1	c.904C>G	p.His302Asp	missense_variant	Exon 11 of 12		NP_001394021.1
OTC	XM_017029556.2	c.*37C>G		downstream_gene_variant			XP_016885045.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
OTC	ENST00000039007.5	c.904C>G	p.His302Asp	missense_variant	Exon 9 of 10	1	NM_000531.6	ENSP00000039007.4
ENSG00000250349	ENST00000465127.1	c.172-254223C>G		intron_variant	Intron 3 of 8	5		ENSP00000417050.1
OTC	ENST00000643344.1	n.*654C>G		non_coding_transcript_exon_variant	Exon 10 of 11			ENSP00000496606.1
OTC	ENST00000643344.1	n.*654C>G		3_prime_UTR_variant	Exon 10 of 11			ENSP00000496606.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 23

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Ornithine carbamoyltransferase deficiency Pathogenic:1

Oct 14, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.His302 amino acid residue in OTC. Other variant(s) that disrupt this residue have been observed in individuals with OTC-related conditions (PMID: 8807340, 9266388, 33272297), which suggests that this may be a clinically significant amino acid residue. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt OTC protein function. This variant has not been reported in the literature in individuals affected with OTC-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces histidine with aspartic acid at codon 302 of the OTC protein (p.His302Asp). The histidine residue is highly conserved and there is a moderate physicochemical difference between histidine and aspartic acid. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.73	D
BayesDel_noAF	Pathogenic	0.81
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.99	D
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	1.0	D
MetaSVM	Pathogenic	0.89	D
MutationAssessor	Pathogenic	4.6	H
PrimateAI	Uncertain	0.69	T
PROVEAN	Pathogenic	-8.6	D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.99		Loss of catalytic residue at C303 (P = 0.0429);
MVP		0.98
MPC		1.4
ClinPred		1.0	D
GERP RS		5.0
Varity_R		1.0
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.23		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.23		Position offset: 1

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: chrX-38271151;