chr3-63912789-G-C

Position:

• chr3-63912789-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001377405.1(ATXN7):​c.191G>C​(p.Gly64Ala) 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. 13/21 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: ATXN7 NM_001377405.1 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.10

Genes affected

ATXN7 (HGNC:10560): (ataxin 7) The autosomal dominant cerebellar ataxias (ADCA) are a heterogeneous group of neurodegenerative disorders characterized by progressive degeneration of the cerebellum, brain stem and spinal cord. Clinically, ADCA has been divided into three groups: ADCA types I-III. ADCAI is genetically heterogeneous, with five genetic loci, designated spinocerebellar ataxia (SCA) 1, 2, 3, 4 and 6, being assigned to five different chromosomes. ADCAII, which always presents with retinal degeneration (SCA7), and ADCAIII often referred to as the 'pure' cerebellar syndrome (SCA5), are most likely homogeneous disorders. Several SCA genes have been cloned and shown to contain CAG repeats in their coding regions. ADCA is caused by the expansion of the CAG repeats, producing an elongated polyglutamine tract in the corresponding protein. The expanded repeats are variable in size and unstable, usually increasing in size when transmitted to successive generations. This locus has been mapped to chromosome 3, and it has been determined that the diseased allele associated with spinocerebellar ataxia-7 contains 37-306 CAG repeats (near the N-terminus), compared to 4-35 in the normal allele. The encoded protein is a component of the SPT3/TAF9/GCN5 acetyltransferase (STAGA) and TBP-free TAF-containing (TFTC) chromatin remodeling complexes, and it thus plays a role in transcriptional regulation. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.14073128).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ATXN7	NM_001377405.1	c.191G>C	p.Gly64Ala	missense_variant	3/13	ENST00000674280.1
ATXN7	NM_001177387.1	c.191G>C	p.Gly64Ala	missense_variant	2/13
ATXN7	NM_000333.4	c.191G>C	p.Gly64Ala	missense_variant	3/13
ATXN7	NM_001377406.1	c.191G>C	p.Gly64Ala	missense_variant	2/12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ATXN7	ENST00000674280.1	c.191G>C	p.Gly64Ala	missense_variant	3/13		NM_001377405.1	P2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 05, 2024

The c.191G>C (p.G64A) alteration is located in exon 2 (coding exon 1) of the ATXN7 gene. This alteration results from a G to C substitution at nucleotide position 191, causing the glycine (G) at amino acid position 64 to be replaced by an alanine (A). 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	0.10
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.45
CADD	Benign	23
DANN	Uncertain	0.99
DEOGEN2	Benign	0.11	.;T;.;T;.
Eigen	Benign	-0.15
Eigen_PC	Benign	-0.073
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Benign	0.55	T;T;T;.;.
M_CAP	Benign	0.049	D
MetaRNN	Benign	0.14	T;T;T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.81	.;L;L;L;L
MutationTaster	Benign	0.98	N;N;N;N
PrimateAI	Pathogenic	0.84	D
PROVEAN	Benign	-0.29	.;N;N;N;.
REVEL	Benign	0.018
Sift	Benign	0.10	.;T;T;T;.
Sift4G	Pathogenic	0.0	.;D;T;D;.
Polyphen		0.092, 0.48	.;B;P;B;P
Vest4		0.13, 0.12, 0.15
MutPred		0.16		Gain of relative solvent accessibility (P = 0.0166);Gain of relative solvent accessibility (P = 0.0166);Gain of relative solvent accessibility (P = 0.0166);Gain of relative solvent accessibility (P = 0.0166);Gain of relative solvent accessibility (P = 0.0166);
MVP		0.42
ClinPred		0.38	T
GERP RS		3.6
Varity_R		0.078
gMVP		0.25

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr3-63898465;