2-74135659-C-G

Variant names:

• chr2-74135659-C-G
• NM_212552.3:c.259-1G>C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_212552.3(BOLA3):​c.259-1G>C variant causes a splice acceptor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: BOLA3 NM_212552.3 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 5.34

Genes affected

BOLA3 (HGNC:24415): (bolA family member 3) This gene encodes a protein that plays an essential role in the production of iron-sulfur (Fe-S) clusters for the normal maturation of lipoate-containing 2-oxoacid dehydrogenases, and for the assembly of the mitochondrial respiratory chain complexes. Mutation in this gene has been associated with multiple mitochondrial dysfunctions syndrome-2. Two alternatively spliced transcript variants encoding different isoforms with distinct subcellular localization have been reported for this gene (PMID:21944046). [provided by RefSeq, Dec 2011]

TET3 (HGNC:28313): (tet methylcytosine dioxygenase 3) Enables methyl-CpG binding activity and zinc ion binding activity. Involved in histone H3-K4 trimethylation; positive regulation of transcription by RNA polymerase II; and protein O-linked glycosylation. Predicted to be located in cytoplasm and male pronucleus. Predicted to be active in nucleus. Biomarker of esophagus squamous cell carcinoma. [provided by Alliance of Genome Resources, Apr 2022]

ENSG00000217702 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease,
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-74135659-C-G is Pathogenic according to our data. Variant chr2-74135659-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2577215.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BOLA3	NM_212552.3	c.259-1G>C		splice_acceptor_variant, intron_variant	Intron 3 of 3	ENST00000327428.10	NP_997717.2
BOLA3	NM_001035505.2	c.170-1G>C		splice_acceptor_variant, intron_variant	Intron 2 of 2		NP_001030582.1
TET3	XM_024452745.2	c.*416C>G		downstream_gene_variant			XP_024308513.1
TET3	XM_024452746.2	c.*416C>G		downstream_gene_variant			XP_024308514.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BOLA3	ENST00000327428.10	c.259-1G>C		splice_acceptor_variant, intron_variant	Intron 3 of 3	1	NM_212552.3	ENSP00000331369.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Multiple mitochondrial dysfunctions syndrome 2 Pathogenic:1

Jul 11, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: BOLA3 c.259-1G>C is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 3' acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant was absent in 251334 control chromosomes. To our knowledge, no occurrence of c.259-1G>C in individuals affected with Multiple Mitochondrial Dysfunctions Syndrome 2 and no experimental evidence demonstrating its impact on protein function have been reported. No submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.92
FATHMM_MKL	Pathogenic	0.98	D
GERP RS		4.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.27		Position offset: -11
DS_AL_spliceai		0.96		Position offset: -1

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-74362786;