rs72554310

Positions:

• chrX-38367344-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PP3_Strong PP5_Moderate

The NM_000531.6(OTC):​c.131C>T​(p.Thr44Ile) variant causes a missense change. 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 (★). Synonymous variant affecting the same amino acid position (i.e. T44T) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 22)
• Consequence: OTC NM_000531.6 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 6.30

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 7 uncertain in NM_000531.6
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991
• PP5: Variant X-38367344-C-T is Pathogenic according to our data. Variant chrX-38367344-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 97109.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
OTC	NM_000531.6	c.131C>T	p.Thr44Ile	missense_variant	2/10	ENST00000039007.5
OTC	NM_001407092.1	c.131C>T	p.Thr44Ile	missense_variant	4/12
OTC	XM_017029556.2	c.131C>T	p.Thr44Ile	missense_variant	2/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
OTC	ENST00000039007.5	c.131C>T	p.Thr44Ile	missense_variant	2/10	1	NM_000531.6	P1
OTC	ENST00000488812.1	n.223C>T		non_coding_transcript_exon_variant	2/6	5
OTC	ENST00000643344.1	c.131C>T	p.Thr44Ile	missense_variant, NMD_transcript_variant	2/11

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 22

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Ornithine carbamoyltransferase deficiency Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

DASA

Jan 05, 2022

The c.131C>T;p.(Thr44Ile) missense variant has been observed in affected individual(s) and ClinVar contains an entry for this variant (Clinvar ID:97109; PMID: 8830175; 17041896; 25994866) - PS4. Well-established in vitro or in vivo functional studies support a damaging effect on the gene or gene product (PMID: 17041896) - PS3_supporting. This variant is not present in population databases (rs72554310, gnomAD; ABraOM no frequency - http://abraom.ib.usp.br/) - PM2. The variant was assumed de novo, but without confirmation of paternity and maternity (PMID:8830175) - PM6. Missense variant in OTC that has a low rate of benign missense variation and in which missense variants are a common mechanism of disease - PP2. Multiple lines of computational evidence support a deleterious effect on the gene or gene product - PP3. Patient’s phenotype is highly specific for a disease with a single genetic etiology - PP4. In summary, the currently available evidence indicates that the variant is pathogenic. -

not provided Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

GenMed Metabolism Lab

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.78
BayesDel_addAF	Pathogenic	0.69	D
BayesDel_noAF	Pathogenic	0.75
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.97	D
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.60	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.6	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.69	T
PROVEAN	Uncertain	-4.1	D
REVEL	Pathogenic	0.95
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.0080	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.89		Loss of ubiquitination at K46 (P = 0.0653);
MVP		0.99
MPC		1.2
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.98
gMVP		0.98

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: rs72554310; hg19: chrX-38226597;