3-139005923-C-T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001134659.1(PRR23A):c.346G>A(p.Asp116Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: PRR23A NM_001134659.1 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -1.40

Genes affected

PRR23A (HGNC:37172): (proline rich 23A)

MRPS22 (HGNC:14508): (mitochondrial ribosomal protein S22) Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and help in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. They have an estimated 75% protein to rRNA composition compared to prokaryotic ribosomes, where this ratio is reversed. Another difference between mammalian mitoribosomes and prokaryotic ribosomes is that the latter contain a 5S rRNA. Among different species, the proteins comprising the mitoribosome differ greatly in sequence, and sometimes in biochemical properties, which prevents easy recognition by sequence homology. This gene encodes a 28S subunit protein that does not seem to have a counterpart in prokaryotic and fungal-mitochondrial ribosomes. This gene lies telomeric of and is transcribed in the opposite direction from the forkhead box L2 gene. A pseudogene corresponding to this gene is found on chromosome Xq. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.047590077).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PRR23A	NM_001134659.1	c.346G>A	p.Asp116Asn	missense_variant	1/1	ENST00000383163.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PRR23A	ENST00000383163.4	c.346G>A	p.Asp116Asn	missense_variant	1/1		NM_001134659.1	P1
MRPS22	ENST00000495075.5	c.-315C>T		5_prime_UTR_variant	1/10	1		P4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 17, 2023

The c.346G>A (p.D116N) alteration is located in exon 1 (coding exon 1) of the PRR23A gene. This alteration results from a G to A substitution at nucleotide position 346, causing the aspartic acid (D) at amino acid position 116 to be replaced by an asparagine (N). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.092
BayesDel_addAF	Benign	-0.40	T
BayesDel_noAF	Benign	-0.81
Cadd	Benign	1.7
Dann	Benign	0.93
DEOGEN2	Benign	0.0050	T
Eigen	Benign	-1.3
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.0049	N
LIST_S2	Benign	0.38	T
M_CAP	Benign	0.0033	T
MetaRNN	Benign	0.048	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.0	N
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.29	T
PROVEAN	Benign	0.060	N
REVEL	Benign	0.014
Sift	Benign	0.13	T
Sift4G	Benign	0.37	T
Polyphen		0.22	B
Vest4		0.074
MutPred		0.25		Loss of phosphorylation at S119 (P = 0.0987);
MVP		0.030
MPC		0.71
ClinPred		0.086	T
GERP RS		-0.81
Varity_R		0.035
gMVP		0.086

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: rs779029059; hg19: chr3-138724765;