chr8-102214136-C-T

Variant names:

• chr8-102214136-C-T
• rs121918309
• NM_015713.5:c.707G>A

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_015713.5(RRM2B):​c.707G>A​(p.Cys236Tyr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,838 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/22 in silico tools predict a damaging outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C236F) has been classified as Pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: RRM2B NM_015713.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.86
• Publications: 0 publications found

Genes affected

RRM2B (HGNC:17296): (ribonucleotide reductase regulatory TP53 inducible subunit M2B) This gene encodes the small subunit of a p53-inducible ribonucleotide reductase. This heterotetrameric enzyme catalyzes the conversion of ribonucleoside diphosphates to deoxyribonucleoside diphosphates. The product of this reaction is necessary for DNA synthesis. Mutations in this gene have been associated with autosomal recessive mitochondrial DNA depletion syndrome, autosomal dominant progressive external ophthalmoplegia-5, and mitochondrial neurogastrointestinal encephalopathy. Alternatively spliced transcript variants have been described.[provided by RefSeq, Feb 2010]

RRM2B Gene-Disease associations (from GenCC):

• mitochondrial DNA depletion syndrome 8a

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Orphanet
• progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 5

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• adult-onset chronic progressive external ophthalmoplegia with mitochondrial myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal dominant progressive external ophthalmoplegia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Kearns-Sayre syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• mitochondrial neurogastrointestinal encephalomyopathy

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PM1: In a helix (size 25) in uniprot entity RIR2B_HUMAN there are 4 pathogenic changes around while only 0 benign (100%) in NM_015713.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr8-102214136-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 5390.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.971

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
RRM2B	NM_015713.5	c.707G>A	p.Cys236Tyr	missense_variant	Exon 7 of 9	ENST00000251810.8	NP_056528.2
RRM2B	NM_001172477.1	c.923G>A	p.Cys308Tyr	missense_variant	Exon 7 of 9		NP_001165948.1
RRM2B	NM_001172478.2	c.551G>A	p.Cys184Tyr	missense_variant	Exon 6 of 8		NP_001165949.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
RRM2B	ENST00000251810.8	c.707G>A	p.Cys236Tyr	missense_variant	Exon 7 of 9	1	NM_015713.5	ENSP00000251810.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460838 Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0 AN XY: 726800

⚠️ 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: 33436

American (AMR) AF: 0.00 AC: 0 AN: 44694

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26108

East Asian (EAS) AF: 0.00 AC: 0 AN: 39602

South Asian (SAS) AF: 0.00 AC: 0 AN: 86240

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53320

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 9.00e-7 AC: 1 AN: 1111334

Other (OTH) AF: 0.00 AC: 0 AN: 60344

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;T;.;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D;D;D;D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.97	D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.0	H;.;.;.
PhyloP100		7.9
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-9.3	D;.;D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;.;D;D
Sift4G	Uncertain	0.037	D;D;D;D
Polyphen		1.0	D;.;D;D
Vest4		0.97
MutPred		0.85		Loss of catalytic residue at L237 (P = 0.0169);.;.;.;
MVP		1.0
MPC		1.5
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.99
gMVP		0.87
Mutation Taster		=2/98	disease causing

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

Other links and lift over

dbSNP: rs121918309; hg19: chr8-103226364;