rs772385806

Variant names:

• chr16-81377546-C-T
• rs772385806
• NM_022041.4:c.1744C>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_022041.4(GAN):​c.1744C>T​(p.Arg582Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000274 in 1,461,846 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R582L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: GAN NM_022041.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.81
• Publications: 0 publications found

Genes affected

GAN (HGNC:4137): (gigaxonin) This gene encodes a member of the cytoskeletal BTB/kelch (Broad-Complex, Tramtrack and Bric a brac) repeat family. The encoded protein plays a role in neurofilament architecture and is involved in mediating the ubiquitination and degradation of some proteins. Defects in this gene are a cause of giant axonal neuropathy (GAN). [provided by RefSeq, Oct 2008]

GAN Gene-Disease associations (from GenCC):

• giant axonal neuropathy 1

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 11 curated pathogenic missense variants (we use a threshold of 10). The gene has 3 curated benign missense variants. Trascript score misZ: -2.0288 (below the threshold of 3.09). GenCC associations: The gene is linked to giant axonal neuropathy 1.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.812

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GAN	NM_022041.4	c.1744C>T	p.Arg582Cys	missense_variant	Exon 11 of 11	ENST00000648994.2	NP_071324.1
GAN	NM_001377486.1	c.1105C>T	p.Arg369Cys	missense_variant	Exon 10 of 10		NP_001364415.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GAN	ENST00000648994.2	c.1744C>T	p.Arg582Cys	missense_variant	Exon 11 of 11		NM_022041.4	ENSP00000497351.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250794 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461846 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727230

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.0000224 AC: 1 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

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

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

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

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111970

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Giant axonal neuropathy 1 Uncertain:1

Jul 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 569005). This variant has not been reported in the literature in individuals affected with GAN-related conditions. This variant is present in population databases (rs772385806, gnomAD 0.003%). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 582 of the GAN protein (p.Arg582Cys). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.43
BayesDel_addAF	Uncertain	0.11	D
BayesDel_noAF	Uncertain	0.0
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.31	T;T
Eigen	Uncertain	0.49
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	.;D
M_CAP	Benign	0.071	D
MetaRNN	Pathogenic	0.81	D;D
MetaSVM	Uncertain	-0.23	T
MutationAssessor	Benign	0.81	L;L
PhyloP100		4.8
PrimateAI	Pathogenic	0.84	D
Sift4G	Uncertain	0.0060	D;.
Polyphen		1.0	D;D
Vest4		0.48
MutPred		0.70		Gain of sheet (P = 1e-04);Gain of sheet (P = 1e-04);
MVP		0.80
MPC		0.51
ClinPred		0.96	D
GERP RS		5.6
Varity_R		0.17
gMVP		0.80
Mutation Taster		=80/20	polymorphism

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: rs772385806; hg19: chr16-81411151; COSMIC: COSV105942108;