NM_000374.5:c.636+1G>C

Variant names:

• chr1-45014071-G-C
• rs145195562
• NM_000374.5:c.636+1G>C

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1_Strong PP5_Very_Strong

The NM_000374.5(UROD):​c.636+1G>C variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000103 in 1,461,876 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: UROD NM_000374.5 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 9.01
• Publications: 4 publications found

Genes affected

UROD (HGNC:12591): (uroporphyrinogen decarboxylase) This gene encodes an enzyme in the heme biosynthetic pathway. This enzyme is responsible for catalyzing the conversion of uroporphyrinogen to coproporphyrinogen through the removal of four carboxymethyl side chains. Mutations and deficiency in this enzyme are known to cause familial porphyria cutanea tarda and hepatoerythropoetic porphyria.[provided by RefSeq, Aug 2010]

UROD Gene-Disease associations (from GenCC):

• UROD-related inherited porphyria

  Inheritance: SD Classification: DEFINITIVE Submitted by: ClinGen, Ambry Genetics
• familial porphyria cutanea tarda

  Inheritance: AD, AR Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)
• hepatoerythropoietic porphyria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

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

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.14673913 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.8, offset of -27, new splice context is: ctgGTagga. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PP5: Variant 1-45014071-G-C is Pathogenic according to our data. Variant chr1-45014071-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 67.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000374.5. 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
	UROD	NM_000374.5	MANE Select	c.636+1G>C		splice_donor intron	N/A	NP_000365.3
	UROD	NR_036510.2		n.698+1G>C		splice_donor intron	N/A
	UROD	NR_158184.1		n.717+1G>C		splice_donor intron	N/A

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	UROD	ENST00000246337.9	TSL:1 MANE Select	c.636+1G>C		splice_donor intron	N/A	ENSP00000246337.4
	UROD	ENST00000460906.5	TSL:5	n.771G>C		non_coding_transcript_exon	Exon 5 of 5
	UROD	ENST00000472254.1	TSL:2	n.22G>C		non_coding_transcript_exon	Exon 1 of 4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000278 AC: 7 AN: 251372 AF XY: 0.0000221

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000615

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1461876 Hom.: 0 Cov.: 34 AF XY: 0.00000825 AC XY: 6 AN XY: 727244

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53404

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000126 AC: 14 AN: 1112010

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ESP6500AA AF: 0.00 AC: 0

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000576 AC: 7

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

Jan 22, 2024

Mayo Clinic Laboratories, Mayo Clinic

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PM2_moderate, PS4, PVS1

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 6 of the UROD gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in UROD are known to be pathogenic (PMID: 1634232, 17240319, 19233912, 19419417, 23545314). This variant is present in population databases (rs145195562, gnomAD 0.006%). Disruption of this splice site has been observed in individuals with autosomal dominant porphyria cutanea tarda (PMID: 2243121). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 67). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic.

Familial porphyria cutanea tarda Pathogenic:1 Other:1

Nov 01, 1990

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		9.0
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.7
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.90		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.46		Position offset: -28
DS_DL_spliceai		0.90		Position offset: -1

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

Other links and lift over

dbSNP: rs145195562; hg19: chr1-45479743;