NM_022041.4:c.683C>A

Variant names:

• chr16-81356834-C-A
• rs1301648787
• NM_022041.4:c.683C>A

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_022041.4(GAN):​c.683C>A​(p.Ser228Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,622 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 11/19 in silico tools predict a benign 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. S228P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: GAN NM_022041.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.69
• Publications: 1 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 1 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.24684548).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GAN	NM_022041.4	c.683C>A	p.Ser228Tyr	missense_variant	Exon 4 of 11	ENST00000648994.2	NP_071324.1
GAN	NM_001377486.1	c.44C>A	p.Ser15Tyr	missense_variant	Exon 3 of 10		NP_001364415.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GAN	ENST00000648994.2	c.683C>A	p.Ser228Tyr	missense_variant	Exon 4 of 11		NM_022041.4	ENSP00000497351.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251490 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461622 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727144

African (AFR) AF: 0.00 AC: 0 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

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: 1111772

Other (OTH) AF: 0.00 AC: 0 AN: 60384

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Giant axonal neuropathy 1 Uncertain:1

Dec 22, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (ExAC no frequency). 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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with GAN-related disease. This sequence change replaces serine with tyrosine at codon 228 of the GAN protein (p.Ser228Tyr). The serine residue is moderately conserved and there is a large physicochemical difference between serine and tyrosine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.20
BayesDel_addAF	Benign	-0.040	T
BayesDel_noAF	Benign	-0.29
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.42	T;T
Eigen	Benign	0.084
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.90	.;D
M_CAP	Benign	0.0069	T
MetaRNN	Benign	0.25	T;T
MetaSVM	Benign	-0.66	T
MutationAssessor	Benign	1.2	L;L
PhyloP100		3.7
PrimateAI	Uncertain	0.52	T
Sift4G	Benign	0.38	T;.
Polyphen		0.044	B;B
Vest4		0.55
MutPred		0.33		Gain of phosphorylation at S228 (P = 0.0502);Gain of phosphorylation at S228 (P = 0.0502);
MVP		0.78
MPC		0.19
ClinPred		0.62	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.51
gMVP		0.36

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: rs1301648787; hg19: chr16-81390439;