chr7-75981607-G-T

Variant names:

• chr7-75981607-G-T
• rs786205099
• NM_001395413.1:c.722+1G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_001395413.1(POR):​c.722+1G>T variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,800 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: POR NM_001395413.1 splice_donor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.72
• 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 Submitted by: ClinGen, 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 0.044247787 fraction of the gene. Cryptic splice site detected, with MaxEntScore 9.1, offset of 18, new splice context is: cagGTgcgg. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001395413.1. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	POR	NM_001395413.1	MANE Select	c.722+1G>T		splice_donor intron	N/A	NP_001382342.1	P16435
	POR	NM_001382655.3		c.776+1G>T		splice_donor intron	N/A	NP_001369584.2
	POR	NM_001367562.3		c.722+1G>T		splice_donor intron	N/A	NP_001354491.2	P16435

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	POR	ENST00000461988.6	TSL:1 MANE Select	c.722+1G>T		splice_donor intron	N/A	ENSP00000419970.2	P16435
	POR	ENST00000447222.5	TSL:5	c.881+1G>T		splice_donor intron	N/A	ENSP00000393527.1	H0Y4R2
	POR	ENST00000910548.1		c.722+1G>T		splice_donor intron	N/A	ENSP00000580607.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459800 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726148

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33446

American (AMR) AF: 0.00 AC: 0 AN: 44486

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26056

East Asian (EAS) AF: 0.00 AC: 0 AN: 39668

South Asian (SAS) AF: 0.00 AC: 0 AN: 85990

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52836

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5752

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111260

Other (OTH) AF: 0.00 AC: 0 AN: 60306

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Uncertain	0.070
CADD	Pathogenic	36
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.88
FATHMM_MKL	Uncertain	0.96	D
PhyloP100		7.7
GERP RS		4.2
PromoterAI		-0.030	Neutral
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.97		Position offset: 17
DS_DL_spliceai		1.0		Position offset: -1

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

Other links and lift over

dbSNP: rs786205099; hg19: chr7-75610925;