chr16-81377585-C-T

Position:

• chr16-81377585-C-T

Variant summary

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

The NM_022041.4(GAN):​c.1783C>T​(p.His595Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,752 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 11/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar 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, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.01

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]

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=0.13927722).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GAN	NM_022041.4	c.1783C>T	p.His595Tyr	missense_variant	11/11	ENST00000648994.2	NP_071324.1
GAN	NM_001377486.1	c.1144C>T	p.His382Tyr	missense_variant	10/10		NP_001364415.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GAN	ENST00000648994.2	c.1783C>T	p.His595Tyr	missense_variant	11/11		NM_022041.4	ENSP00000497351	P1
GAN	ENST00000648349.2	c.*1491C>T		3_prime_UTR_variant, NMD_transcript_variant	10/10			ENSP00000498114
GAN	ENST00000650388.1	c.*1140C>T		3_prime_UTR_variant, NMD_transcript_variant	9/9			ENSP00000498081

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250828 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135534

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS 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: 0.00000205 AC: 3 AN: 1461752 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727200

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Giant axonal neuropathy 1 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 01, 2021	This sequence change replaces histidine with tyrosine at codon 595 of the GAN protein (p.His595Tyr). The histidine residue is weakly conserved and there is a moderate physicochemical difference between histidine and tyrosine. This variant is present in population databases (rs757216350, ExAC 0.01%). This variant has not been reported in the literature in individuals affected with GAN-related conditions. 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. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.18	T
BayesDel_noAF	Benign	-0.33
CADD	Benign	21
DANN	Benign	0.97
DEOGEN2	Benign	0.17	T;T
Eigen	Benign	-0.62
Eigen_PC	Benign	-0.46
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Benign	0.84	.;T
M_CAP	Benign	0.014	T
MetaRNN	Benign	0.14	T;T
MetaSVM	Benign	-0.76	T
MutationAssessor	Benign	0.0	N;N
MutationTaster	Benign	0.53	N
PrimateAI	Uncertain	0.63	T
Sift4G	Benign	0.55	T;.
Polyphen		0.054	B;B
Vest4		0.20
MutPred		0.32		Gain of sheet (P = 0.039);Gain of sheet (P = 0.039);
MVP		0.70
MPC		0.15
ClinPred		0.095	T
GERP RS		4.6
Varity_R		0.063
gMVP		0.43

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs757216350; hg19: chr16-81411190;