2-86027972-G-A

Position:

• chr2-86027972-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_015425.6(POLR1A):​c.4975C>T​(p.Arg1659Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,866 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: POLR1A NM_015425.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.51

Genes affected

POLR1A (HGNC:17264): (RNA polymerase I subunit A) The protein encoded by this gene is the largest subunit of the RNA polymerase I complex. The encoded protein represents the catalytic subunit of the complex, which transcribes DNA into ribosomal RNA precursors. Defects in this gene are a cause of the Cincinnati type of acrofacial dysostosis. [provided by RefSeq, May 2016]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), POLR1A. . Gene score misZ 2.9485 (greater than the threshold 3.09). Trascript score misZ 4.9691 (greater than threshold 3.09). GenCC has associacion of gene with acrofacial dysostosis Cincinnati type, choanal atresia-hearing loss-cardiac defects-craniofacial dysmorphism syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
POLR1A	NM_015425.6	c.4975C>T	p.Arg1659Cys	missense_variant	33/34	ENST00000263857.11	NP_056240.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
POLR1A	ENST00000263857.11	c.4975C>T	p.Arg1659Cys	missense_variant	33/34	1	NM_015425.6	ENSP00000263857	P2
POLR1A	ENST00000409681.1	c.4792C>T	p.Arg1598Cys	missense_variant	33/34	5		ENSP00000386300	A2
POLR1A	ENST00000471427.1	n.284C>T		non_coding_transcript_exon_variant	2/2	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461866 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727244

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 24, 2022

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt POLR1A protein function. ClinVar contains an entry for this variant (Variation ID: 1506712). This variant has not been reported in the literature in individuals affected with POLR1A-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 1659 of the POLR1A protein (p.Arg1659Cys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.82	D;D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Uncertain	0.77	D
MutationAssessor	Pathogenic	4.1	H;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-7.1	D;D
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.96
MutPred		0.93		Loss of disorder (P = 0.0306);.;
MVP		0.82
MPC		1.1
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.89
gMVP		0.98

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: rs1672302366; hg19: chr2-86255095;