NM_000531.6:c.77+4A>C

Variant names:

• chrX-38352777-A-C
• rs72552301
• NM_000531.6:c.77+4A>C

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PM2 PP5 BP4

The NM_000531.6(OTC):​c.77+4A>C variant causes a splice region, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic (no stars).

• Frequency: Genomes: not found (cov: 23)
• Consequence: OTC NM_000531.6 splice_region, intron
• Scores: Splicing: ADA: 0.7143
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 4.73
• Publications: 1 publications found

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]

OTC Gene-Disease associations (from GenCC):

• ornithine carbamoyltransferase deficiency

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, G2P, Laboratory for Molecular Medicine, Orphanet

ENSG00000250349 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-38352777-A-C is Pathogenic according to our data. Variant chrX-38352777-A-C is described in ClinVar as Pathogenic. ClinVar VariationId is 97316.Status of the report is no_assertion_criteria_provided, 0 stars.
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.41). . Strength limited to SUPPORTING due to the PP5.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000531.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	OTC	NM_000531.6	MANE Select	c.77+4A>C		splice_region intron	N/A	NP_000522.3
	OTC	NM_001407092.1		c.77+4A>C		splice_region intron	N/A	NP_001394021.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	OTC	ENST00000039007.5	TSL:1 MANE Select	c.77+4A>C		splice_region intron	N/A	ENSP00000039007.4
	ENSG00000250349	ENST00000465127.1	TSL:5	c.172-313344A>C		intron	N/A	ENSP00000417050.1
	OTC	ENST00000713758.1		c.77+4A>C		splice_region intron	N/A	ENSP00000519059.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 25

GnomAD4 genome Cov.: 23

Alfa AF: 0.0000427 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

not provided Pathogenic:1

GenMed Metabolism Lab

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.41
CADD	Benign	22
DANN	Benign	0.95
PhyloP100		4.7
PromoterAI		-0.16	Neutral
Mutation Taster		=77/23	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.71
dbscSNV1_RF	Benign	0.51
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs72552301; hg19: chrX-38212030;