NM_006796.3:c.1997T>C

Variant names:

• chr18-12337519-A-G
• rs151344515
• NM_006796.3:c.1997T>C

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_006796.3(AFG3L2):​c.1997T>C​(p.Met666Thr) 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. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M666R) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: AFG3L2 NM_006796.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 8.91
• Publications: 12 publications found

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]

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]

TUBB6 Gene-Disease associations (from GenCC):

• facial palsy, congenital, with ptosis and velopharyngeal dysfunction

  Inheritance: Unknown Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

LOC107985154 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 13 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 2 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 chr18-12337519-A-C is described in ClinVar as Pathogenic. ClinVar VariationId is 30424.Status of the report is no_assertion_criteria_provided, 0 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 37 curated pathogenic missense variants (we use a threshold of 10). The gene has 9 curated benign missense variants. Gene score misZ: 1.988 (below the threshold of 3.09). Trascript score misZ: 3.0639 (below the threshold of 3.09). GenCC associations: The gene is linked to spastic ataxia 5, optic atrophy 12, spinocerebellar ataxia type 28.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.981
• PP5: Variant 18-12337519-A-G is Pathogenic according to our data. Variant chr18-12337519-A-G is described in ClinVar as Pathogenic. ClinVar VariationId is 38389.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AFG3L2	NM_006796.3	c.1997T>C	p.Met666Thr	missense_variant	Exon 16 of 17	ENST00000269143.8	NP_006787.2
AFG3L2	XM_011525601.4	c.1796T>C	p.Met599Thr	missense_variant	Exon 15 of 16		XP_011523903.1
LOC107985154	XR_002958227.2	n.3291+617A>G		intron_variant	Intron 1 of 1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AFG3L2	ENST00000269143.8	c.1997T>C	p.Met666Thr	missense_variant	Exon 16 of 17	1	NM_006796.3	ENSP00000269143.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Oct 29, 2024

Athena Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in large, multi-ethnic general populations. (http://gnomad.broadinstitute.org) This variant has been identified in at least one individual with clinical features associated with this gene. Assessment of experimental evidence suggests this variant results in abnormal protein function. (PMID: 30910913) At least one other missense variant at this codon is considered to be pathogenic or likely pathogenic, suggesting this variant may also cause disease. -

Spinocerebellar ataxia type 28 Other:1

-

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	29
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	Uncertain	0.97	D
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.8	H
PhyloP100		8.9
PrimateAI	Pathogenic	0.90	D
PROVEAN	Pathogenic	-5.5	D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.88		Loss of stability (P = 0.0969);
MVP		0.96
MPC		0.77
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.96
gMVP		0.95
Mutation Taster		=0/100	disease causing (ClinVar)

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: rs151344515; hg19: chr18-12337518;