rs556445621

Variant names:

• chr10-100989382-G-A
• rs556445621
• NM_021830.5:c.1172G>A

Your query was ambiguous. Multiple possible variants found:

• chr10-100989382-G-A
• chr10-100989382-G-C
• chr10-100989382-G-T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 3P and 2B. PM1 PP2 BP4_Moderate

The NM_021830.5(TWNK):​c.1172G>A​(p.Arg391His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000285 in 1,614,146 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R391C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000029 (0 hom.)
• Consequence: TWNK NM_021830.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1 B:4 O:1
• Conservation: PhyloP100: 2.65
• Publications: 16 publications found

Genes affected

TWNK (HGNC:1160): (twinkle mtDNA helicase) This gene encodes a hexameric DNA helicase which unwinds short stretches of double-stranded DNA in the 5' to 3' direction and, along with mitochondrial single-stranded DNA binding protein and mtDNA polymerase gamma, is thought to play a key role in mtDNA replication. The protein localizes to the mitochondrial matrix and mitochondrial nucleoids. Mutations in this gene cause infantile onset spinocerebellar ataxia (IOSCA) and progressive external ophthalmoplegia (PEO) and are also associated with several mitochondrial depletion syndromes. Alternative splicing results in multiple transcript variants encoding distinct isoforms.[provided by RefSeq, Aug 2009]

MRPL43 (HGNC:14517): (mitochondrial ribosomal protein L43) 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 39S subunit protein. This gene and the gene for a semaphorin class 4 protein (SEMA4G) overlap at map location 10q24.31 and are transcribed in opposite directions. Sequence analysis identified multiple transcript variants encoding at least four different protein isoforms. [provided by RefSeq, Jul 2008]

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_021830.5
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 36 curated pathogenic missense variants (we use a threshold of 10). The gene has 6 curated benign missense variants. Gene score misZ: 1.6071 (below the threshold of 3.09). Trascript score misZ: 2.58 (below the threshold of 3.09). GenCC associations: The gene is linked to progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 3, mitochondrial DNA depletion syndrome 7 (hepatocerebral type), Perrault syndrome, autosomal dominant progressive external ophthalmoplegia, mitochondrial DNA depletion syndrome, hepatocerebrorenal form.
• BP4: Computational evidence support a benign effect (MetaRNN=0.21148595).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_021830.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TWNK	NM_021830.5	MANE Select	c.1172G>A	p.Arg391His	missense	Exon 1 of 5	NP_068602.2
	TWNK	NM_001163812.2		c.1172G>A	p.Arg391His	missense	Exon 1 of 5	NP_001157284.1	Q96RR1-2
	TWNK	NM_001163813.2		c.-119-262G>A		intron	N/A	NP_001157285.1	A0A2R8Y4V4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	TWNK	ENST00000311916.8	TSL:1 MANE Select	c.1172G>A	p.Arg391His	missense	Exon 1 of 5	ENSP00000309595.2	Q96RR1-1
	TWNK	ENST00000370228.2	TSL:1	c.1172G>A	p.Arg391His	missense	Exon 1 of 5	ENSP00000359248.1	Q96RR1-2
	MRPL43	ENST00000858454.1		c.-306C>T		5_prime_UTR	Exon 1 of 4	ENSP00000528513.1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152166 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000386

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

GnomAD2 exomes AF: 0.0000636 AC: 16 AN: 251376 AF XY: 0.0000515

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.0000992

Gnomad EAS exome AF: 0.000544

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000294 AC: 43 AN: 1461862 Hom.: 0 Cov.: 32 AF XY: 0.0000206 AC XY: 15 AN XY: 727234

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.0000447 AC: 2 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.0000383 AC: 1 AN: 26136

East Asian (EAS) AF: 0.000277 AC: 11 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53392

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000252 AC: 28 AN: 1112010

Other (OTH) AF: 0.0000166 AC: 1 AN: 60394

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152284 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74468

African (AFR) AF: 0.00 AC: 0 AN: 41550

American (AMR) AF: 0.00 AC: 0 AN: 15304

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.000386 AC: 2 AN: 5176

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68014

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.0000228 Hom.: 0

Bravo AF: 0.0000567

ExAC AF: 0.0000659 AC: 8

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
1	1	-	not provided (2)
-	-	1	Autosomal recessive cerebellar ataxia (1)
-	-	1	Infantile onset spinocerebellar ataxia (1)
1	-	-	Perrault syndrome 5 (1)
-	-	1	Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 3 (1)
-	-	1	Sensory ataxic neuropathy, dysarthria, and ophthalmoparesis (1)
-	-	-	Perrault syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.088
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.23
CADD	Benign	23
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.76	D
Eigen	Benign	-0.33
Eigen_PC	Benign	-0.29
FATHMM_MKL	Uncertain	0.77	D
LIST_S2	Uncertain	0.87	D
M_CAP	Pathogenic	0.57	D
MetaRNN	Benign	0.21	T
MetaSVM	Uncertain	0.36	D
MutationAssessor	Benign	1.8	L
PhyloP100		2.7
PROVEAN	Uncertain	-3.0	D
REVEL	Pathogenic	0.75
Sift	Uncertain	0.0040	D
Sift4G	Uncertain	0.0050	D
Polyphen		0.99	D
Vest4		0.65
MutPred		0.52		Loss of MoRF binding (P = 0.0253)
MVP		0.68
MPC		0.67
ClinPred		0.10	T
GERP RS		3.2
Varity_R		0.090
gMVP		0.43
Mutation Taster		=31/69	disease causing

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

Other links and lift over

dbSNP: rs556445621; hg19: chr10-102749139; COSMIC: COSV99272667; COSMIC: COSV99272667;