rs146301349

chr15-89316819-G-A

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Strong BP6 BP7

The NM_002693.3(POLG):c.3652C>T(p.Leu1218=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000731 in 1,613,442 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. L1218L) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00028 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000051 (0 hom.)
• Consequence: POLG NM_002693.3 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:4
• Conservation: PhyloP100: 2.71

Genes affected

POLG (HGNC:9179): (DNA polymerase gamma, catalytic subunit) Mitochondrial DNA polymerase is heterotrimeric, consisting of a homodimer of accessory subunits plus a catalytic subunit. The protein encoded by this gene is the catalytic subunit of mitochondrial DNA polymerase. The encoded protein contains a polyglutamine tract near its N-terminus that may be polymorphic. Defects in this gene are a cause of progressive external ophthalmoplegia with mitochondrial DNA deletions 1 (PEOA1), sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO), Alpers-Huttenlocher syndrome (AHS), and mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE). Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Jul 2008]

FANCI (HGNC:25568): (FA complementation group I) The Fanconi anemia complementation group (FANC) currently includes FANCA, FANCB, FANCC, FANCD1 (also called BRCA2), FANCD2, FANCE, FANCF, FANCG, FANCI, FANCJ (also called BRIP1), FANCL, FANCM and FANCN (also called PALB2). The previously defined group FANCH is the same as FANCA. Fanconi anemia is a genetically heterogeneous recessive disorder characterized by cytogenetic instability, hypersensitivity to DNA crosslinking agents, increased chromosomal breakage, and defective DNA repair. The members of the Fanconi anemia complementation group do not share sequence similarity; they are related by their assembly into a common nuclear protein complex. This gene encodes the protein for complementation group I. Alternative splicing results in two transcript variants encoding different isoforms. [provided by RefSeq, Jul 2008]

POLGARF (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.48).
• BP6: Variant 15-89316819-G-A is Benign according to our data. Variant chr15-89316819-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 206489.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Benign=1, Likely_benign=3}. Variant chr15-89316819-G-A is described in Lovd as [Likely_benign].
• BP7: Synonymous conserved (PhyloP=2.71 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
POLG	NM_002693.3	c.3652C>T	p.Leu1218=	synonymous_variant	23/23	ENST00000268124.11
FANCI	NM_001113378.2	c.*360G>A		3_prime_UTR_variant	38/38	ENST00000310775.12
POLGARF	NM_001406557.1	c.*2924C>T		3_prime_UTR_variant	23/23

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POLG	ENST00000268124.11	c.3652C>T	p.Leu1218=	synonymous_variant	23/23	1	NM_002693.3	P1
FANCI	ENST00000310775.12	c.*360G>A		3_prime_UTR_variant	38/38	1	NM_001113378.2	P1

Frequencies

GnomAD3 genomes AF: 0.000283 AC: 43 AN: 152156 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000990

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000716 AC: 18 AN: 251352 Hom.: 0 AF XY: 0.0000662 AC XY: 9 AN XY: 135856

Gnomad AFR exome AF: 0.000985

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000513 AC: 75 AN: 1461168 Hom.: 0 Cov.: 30 AF XY: 0.0000523 AC XY: 38 AN XY: 726980

Gnomad4 AFR exome AF: 0.00194

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000540

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.000282 AC: 43 AN: 152274 Hom.: 0 Cov.: 32 AF XY: 0.000269 AC XY: 20 AN XY: 74462

Gnomad4 AFR AF: 0.000987

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000191 Hom.: 0

Bravo AF: 0.000340

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:4

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Progressive sclerosing poliodystrophy Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Wong Mito Lab, Molecular and Human Genetics, Baylor College of Medicine	Oct 01, 2018	The NM_002693.2:c.3652C>T (NP_002684.1:p.Leu1218=) [GRCH38: NC_000015.10:g.89316819G>A] variant in FANCI gene is interpretated to be a Likely Benign based on ACMG guidelines (PMID: 25741868). This variant meets the following evidence codes reported in the ACMG-guideline. BP4:Computational evidence/predictors indicate no impact on the FANCI structure, function, or protein-protein interaction. BP7:The variant is silent with non predicted splice impact. Based on the evidence criteria codes applied, the variant is suggested to be Likely Benign. -
Likely benign, criteria provided, single submitter	clinical testing	Invitae	Jan 11, 2024	- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Aug 22, 2018

- -

not specified Benign:1

Benign, criteria provided, single submitter

clinical testing

GeneDx

Nov 21, 2014

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

POLG-related disorder Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Jan 24, 2023

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.48
Cadd	Benign	11
Dann	Benign	0.90

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: rs146301349; hg19: chr15-89860050;