18-12337519-A-C

Position:

• chr18-12337519-A-C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_006796.3(AFG3L2):​c.1997T>G​(p.Met666Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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 Pathogenic (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M666T) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 33)
• Consequence: AFG3L2 NM_006796.3 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1 O:1
• Conservation: PhyloP100: 8.91

Genes affected

AFG3L2 (HGNC:315): (AFG3 like matrix AAA peptidase subunit 2) This gene encodes a protein localized in mitochondria and closely related to paraplegin. The paraplegin gene is responsible for an autosomal recessive form of hereditary spastic paraplegia. This gene is a candidate gene for other hereditary spastic paraplegias or neurodegenerative disorders. [provided by RefSeq, Jul 2008]

LOC107985154 (HGNC:):

TUBB6 (HGNC:20776): (tubulin beta 6 class V) Predicted to enable GTP binding activity. Predicted to be a structural constituent of cytoskeleton. Predicted to be involved in microtubule cytoskeleton organization and mitotic cell cycle. Located in microtubule. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Pathogenic. Variant got 11 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_006796.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr18-12337520-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 30423.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.982
• PP5: Variant 18-12337519-A-C is Pathogenic according to our data. Variant chr18-12337519-A-C is described in ClinVar as [Pathogenic]. Clinvar id is 30424.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
AFG3L2	NM_006796.3	c.1997T>G	p.Met666Arg	missense_variant	16/17	ENST00000269143.8
LOC107985154	XR_002958227.2	n.3291+617A>C		intron_variant, non_coding_transcript_variant
AFG3L2	XM_011525601.4	c.1796T>G	p.Met599Arg	missense_variant	15/16

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
AFG3L2	ENST00000269143.8	c.1997T>G	p.Met666Arg	missense_variant	16/17	1	NM_006796.3	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: no assertion criteria provided

Submissions by phenotype

Spinocerebellar ataxia type 28 Pathogenic:1 Other:1

not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Oct 01, 2010	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.93	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.97	D
M_CAP	Pathogenic	0.40	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.8	H
MutationTaster	Benign	1.0	D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-5.5	D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.88		Gain of solvent accessibility (P = 0.0273);
MVP		0.96
MPC		0.90
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.98
gMVP		0.98

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs151344515; hg19: chr18-12337518;