chr12-123253706-C-CA

Variant names:

• chr12-123253706-C-CA
• rs2048143498
• NM_152269.5:c.33dupA

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_152269.5(MTRFR):​c.33dupA​(p.Pro12ThrfsTer46) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: MTRFR NM_152269.5 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: -0.843

Genes affected

MTRFR (HGNC:26784): (mitochondrial translation release factor in rescue) This nuclear gene encodes a mitochondrial matrix protein that appears to contribute to peptide chain termination in the mitochondrial translation machinery. Two different 1 bp deletions (resulting in the same premature stop codon)result in decreased mitochondrial translation, decreased levels of oxidative phosphorylation complexes and encepthalomyopathy. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2010]

CDK2AP1 (HGNC:14002): (cyclin dependent kinase 2 associated protein 1) The protein encoded by this gene is a cyclin-dependent kinase 2 (CDK2) -associated protein which is thought to negatively regulate CDK2 activity by sequestering monomeric CDK2, and targeting CDK2 for proteolysis. This protein was found to also interact with DNA polymerase alpha/primase and mediate the phosphorylation of the large p180 subunit, which suggests a regulatory role in DNA replication during the S-phase of the cell cycle. This protein also forms a core subunit of the nucleosome remodeling and histone deacetylation (NURD) complex that epigenetically regulates embryonic stem cell differentiation. This gene thus plays a role in both cell-cycle and epigenetic regulation. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Jul 2012]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.932 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-123253706-C-CA is Pathogenic according to our data. Variant chr12-123253706-C-CA is described in ClinVar as [Pathogenic]. Clinvar id is 859045.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTRFR	NM_152269.5	c.33dupA	p.Pro12ThrfsTer46	frameshift_variant	Exon 2 of 3	ENST00000253233.6	NP_689482.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTRFR	ENST00000253233.6	c.33dupA	p.Pro12ThrfsTer46	frameshift_variant	Exon 2 of 3	1	NM_152269.5	ENSP00000253233.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Spastic paraplegia;C3150801:Combined oxidative phosphorylation defect type 7 Pathogenic:1

Feb 05, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Pro12Thrfs*46) in the C12orf65 gene. It is expected to result in an absent or disrupted protein product. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with C12orf65-related conditions. Loss-of-function variants in C12orf65 are known to be pathogenic (PMID: 20598281, 24424123). For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

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

Publications

LitVar

Other links and lift over

dbSNP: rs2048143498; hg19: chr12-123738253;