rs207460004

chrM-14849-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The ENST00000361789.2(MT-CYB):c.103T>C(p.Ser35Pro) variant causes a missense change. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★★). Another nucleotide change resulting in same amino acid change has been previously reported as Likely benignin UniProt.

• Frequency: Mitomap GenBank: Absent
• Consequence: MT-CYB ENST00000361789.2 missense
• Scores: Apogee2 Pathogenic 0.87
• Clinical Significance: Uncertain significance reviewed by expert panel P:1 U:2 EXIT-/-Septo-Optic-Dysplasia
• Conservation: PhyloP100: 5.74

Genes affected

CYTB (HGNC:):

MT-CYB (HGNC:7427): (mitochondrially encoded cytochrome b) Predicted to enable metal ion binding activity. Predicted to be involved in several processes, including electron transport coupled proton transport; response to cobalamin; and response to glucagon. Located in mitochondrion. Implicated in ovarian carcinoma and urinary bladder cancer. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: No frequency data in Mitomap. Probably very rare.
• PP3: Apogee2 supports a deletorius effect, 0.87056166 >= 0.5 .

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CYTB	CYTB.1	c.103T>C	p.Ser35Pro	missense_variant	1/1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MT-CYB	ENST00000361789.2	c.103T>C	p.Ser35Pro	missense_variant	1/1			P1

Frequencies

GnomAD4 exome Cov.: 0

We have no GnomAD4 genomes data on this position. Probably position not covered by the project.

Alfa AF: 0.000106 Hom.: 0

Mitomap

EXIT-/-Septo-Optic-Dysplasia

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:2

Revision: reviewed by expert panel

Submissions by phenotype

Exercise intolerance, cardiomyopathy, and septooptic dysplasia Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Mar 01, 2002

- -

Mitochondrial disease Uncertain:1

Uncertain significance, reviewed by expert panel

curation

ClinGen Mitochondrial Disease Nuclear and Mitochondrial Variant Curation Expert Panel, ClinGen

Jun 30, 2022

The m.14849T>C (p.S35P) variant in MT-CYB has been reported in two unrelated men. The first reported individual had developmental delay, microcephaly, lactic acidosis and rhabdomyolysis with illness, short stature, dysdiadokinesia, ataxia, exercise intolerance, fatigue, Wolff-Parkinson-White, left ventricular hypertrophy, retinitis pigmentosa, septo-optic dysplasia, and cerebellar hypoplasia (PMID: 11891837) and the second reported individual had exercise intolerance, depressive episodes, and myopathy with ragged red fibers seen on muscle biopsy (PMID: 20544923). Both individuals had onset of features in childhood and heteroplasmy levels in various tissues ranged from 6-85%. Haplogroup information was not reported for all cases precluding consideration for PS4. The variant was reported de novo in the first case report as it was absent in mother’s blood (PMID: 11891837), however no additional tissues were tested and technology performed at the time of publication would not detect low heteroplasmy levels of the variant. There are no large families reported in the medical literature to consider for evidence of segregation. This variant is absent in the GenBank dataset, Helix dataset, and gnomAD v3.1.2 (PM2_supporting). There are no cybrid studies, single fiber studies, or other functional assays reported for this variant. The computational predictor APOGEE gives a consensus rating of pathogenic with a score of 0.74 (Min=0, Max=1), which predicts a damaging effect on gene function (PP3). In summary, this variant meets criteria to be classified as uncertain significance for primary mitochondrial disease inherited in a mitochondrial manner. This classification was approved by the NICHD/NINDS U24 Mitochondrial Disease Variant Curation Expert Panel on May 24, 2022. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID: 32906214): PM2_supporting, PP3. -

Leigh syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine

Oct 17, 2019

The NC_012920.1:m.14849T>C (YP_003024038.1:p.Ser35Pro) variant in MTCYB gene is interpretated to be a Uncertain Significance variant based on the modified ACMG guidelines (unpublished). This variant meets the following evidence codes: PP6, PP7 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
Apogee2	Pathogenic	0.87
Hmtvar	Pathogenic	0.85
AlphaMissense	Pathogenic	0.76

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs207460004; hg19: chrM-14850;