rs936203749

Variant names:

• chr7-75954182-T-C
• rs936203749
• NM_001395413.1:c.179+2T>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PP5_Moderate

The NM_001395413.1(POR):​c.179+2T>C variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.0000181 in 1,605,010 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000019 (0 hom.)
• Consequence: POR NM_001395413.1 splice_donor, intron
• Scores: Splicing: ADA: 0.9042
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.72
• Publications: 0 publications found

Genes affected

POR (HGNC:9208): (cytochrome p450 oxidoreductase) This gene encodes an endoplasmic reticulum membrane oxidoreductase that is essential for multiple metabolic processes, including reactions catalyzed by cytochrome P450 proteins for metabolism of steroid hormones, drugs and xenobiotics. The encoded protein has a flavin adenine dinucleotide (FAD)-binding domain and a flavodoxin-like domain which bind two cofactors, FAD and FMN, that allow it to donate electrons directly from NADPH to all microsomal P450 enzymes. Mutations in this gene cause a complex set of disorders, including apparent combined P450C17 and P450C21 deficiency, amenorrhea and disordered steroidogenesis, congenital adrenal hyperplasia and Antley-Bixler syndrome, that resemble those caused by defects in steroid metabolizing enzymes such as aromatase, 21-hydroxylase, and 17 alpha-hydroxylase. [provided by RefSeq, Aug 2020]

POR Gene-Disease associations (from GenCC):

• Antley-Bixler syndrome with genital anomalies and disordered steroidogenesis

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, PanelApp Australia, Ambry Genetics
• congenital adrenal hyperplasia due to cytochrome P450 oxidoreductase deficiency

  Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
• Antley-Bixler syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.09439528 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PP5: Variant 7-75954182-T-C is Pathogenic according to our data. Variant chr7-75954182-T-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 576622.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
POR	NM_001395413.1	c.179+2T>C		splice_donor_variant, intron_variant	Intron 2 of 15	ENST00000461988.6	NP_001382342.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
POR	ENST00000461988.6	c.179+2T>C		splice_donor_variant, intron_variant	Intron 2 of 15	1	NM_001395413.1	ENSP00000419970.2

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152202 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000425 AC: 1 AN: 235112 AF XY: 0.00000785

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: 0.00000946

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000186 AC: 27 AN: 1452808 Hom.: 0 Cov.: 31 AF XY: 0.0000138 AC XY: 10 AN XY: 722078

African (AFR) AF: 0.00 AC: 0 AN: 33236

American (AMR) AF: 0.00 AC: 0 AN: 43762

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25934

East Asian (EAS) AF: 0.00 AC: 0 AN: 39436

South Asian (SAS) AF: 0.00 AC: 0 AN: 84688

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52980

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5750

European-Non Finnish (NFE) AF: 0.0000235 AC: 26 AN: 1106924

Other (OTH) AF: 0.0000166 AC: 1 AN: 60098

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152202 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74362

African (AFR) AF: 0.00 AC: 0 AN: 41446

American (AMR) AF: 0.00 AC: 0 AN: 15290

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5196

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10612

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000294 AC: 2 AN: 68042

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.0000386 Hom.: 0

Bravo AF: 0.0000151

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital adrenal hyperplasia due to cytochrome P450 oxidoreductase deficiency Pathogenic:1

Oct 26, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 2 of the POR 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 POR are known to be pathogenic (PMID: 14758361, 20732302, 21741353). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with POR-related conditions. ClinVar contains an entry for this variant (Variation ID: 576622). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Benign	-0.13
CADD	Uncertain	24
DANN	Benign	0.95
Eigen	Pathogenic	0.87
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Uncertain	0.92	D
PhyloP100		5.7
GERP RS		4.9
PromoterAI		-0.18	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Mutation Taster		=23/77	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.90
dbscSNV1_RF	Benign	0.51
SpliceAI score (max)		0.73		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.73		Position offset: -2

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

Other links and lift over

dbSNP: rs936203749; hg19: chr7-75583500;