rs139808557

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1PP2PP5

The NM_018972.4(GDAP1):c.399G>A(p.Met133Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000345 in 1,612,736 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M133V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00016 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00036 ( 0 hom. )

Consequence

GDAP1
NM_018972.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4U:3

Conservation

PhyloP100: 7.70

Publications

6 publications found

Variant links:

Genes affected

GDAP1 (HGNC:15968): (ganglioside induced differentiation associated protein 1) This gene encodes a member of the ganglioside-induced differentiation-associated protein family, which may play a role in a signal transduction pathway during neuronal development. Mutations in this gene have been associated with various forms of Charcot-Marie-Tooth Disease and neuropathy. Two transcript variants encoding different isoforms and a noncoding variant have been identified for this gene. [provided by RefSeq, Feb 2012]

GDAP1 Gene-Disease associations (from GenCC):

Charcot-Marie-Tooth disease
Inheritance: SD Classification: DEFINITIVE Submitted by: ClinGen
Charcot-Marie-Tooth disease axonal type 2K
Inheritance: AD, AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
Charcot-Marie-Tooth disease recessive intermediate A
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
autosomal dominant Charcot-Marie-Tooth disease type 2K
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Charcot-Marie-Tooth disease type 4A
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

GDAP1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_018972.4

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 32 curated pathogenic missense variants (we use a threshold of 10). The gene has 3 curated benign missense variants. Gene score misZ: 1.0 (below the threshold of 3.09). Trascript score misZ: 1.1646 (below the threshold of 3.09). GenCC associations: The gene is linked to Charcot-Marie-Tooth disease axonal type 2K, Charcot-Marie-Tooth disease recessive intermediate A, Charcot-Marie-Tooth disease type 4A, Charcot-Marie-Tooth disease, autosomal dominant Charcot-Marie-Tooth disease type 2K.

PP5

Variant 8-74360225-G-A is Pathogenic according to our data. Variant chr8-74360225-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 245607.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GDAP1	NM_018972.4 link	c.399G>A	p.Met133Ile	missense_variant	Exon 3 of 6	ENST00000220822.12	NP_061845.2	Q8TB36-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GDAP1	ENST00000220822.12 link	c.399G>A	p.Met133Ile	missense_variant	Exon 3 of 6	1	NM_018972.4	ENSP00000220822.7		Q8TB36-1

Frequencies

GnomAD3 genomes

AF:

0.000158

AC:

AN:

152054

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000323

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000107

AC:

AN:

251478

AF XY:

0.0000809

show subpopulations

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:

0.000237

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000365

AC:

533

AN:

1460682

Hom.:

Cov.:

AF XY:

0.000336

AC XY:

244

AN XY:

726782

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33452

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.00

AC:

AN:

86236

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000468

AC:

520

AN:

1110910

Other (OTH)

AF:

0.000199

AC:

AN:

60356

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.499

Heterozygous variant carriers

124

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

110

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000158

AC:

AN:

152054

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74248

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41410

American (AMR)

AF:

0.00

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4796

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10596

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000323

AC:

AN:

68008

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000279

Hom.:

Bravo

AF:

0.000174

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.000778

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000741

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4Uncertain:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Jul 02, 2021

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jul 24, 2024

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis indicates that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 14702039, 26392352, 32376792) -

Nov 03, 2023

Mayo Clinic Laboratories, Mayo Clinic

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Charcot-Marie-Tooth disease type 4A

Pathogenic:2

May 21, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: GDAP1 c.399G>A (p.Met133Ile) results in a conservative amino acid change in the encoded protein sequence. 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. The variant allele was found at a frequency of 0.00011 in 251478 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in GDAP1 causing Charcot-Marie-Tooth disease type 4A, allowing no conclusion about variant significance. c.399G>A has been observed in individual(s) affected with autosomal recessive Charcot-Marie-Tooth disease (e.g. Antoniadi_2015, internal data) and in an individual with an unspecified genotype from a Charcot-Marie-Tooth disease cohort (Volodarsky_2021). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 26392352, 32376792). ClinVar contains an entry for this variant (Variation ID: 245607). To our knowledge, this variant has not been reported in individuals with Charcot-Marie-Tooth disease shown to have an autosomal dominant pattern of inheritance. Based on the evidence outlined above, the variant was classified as likely pathogenic for autosomal recessive Charcot-Marie-Tooth disease. -

Dec 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces methionine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 133 of the GDAP1 protein (p.Met133Ile). This variant is present in population databases (rs139808557, gnomAD 0.02%). This missense change has been observed in individual(s) with clinical features of autosomal recessive Charcot-Marie-Tooth disease (PMID: 26392352, 32376792; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 245607). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt GDAP1 protein function with a negative predictive value of 80%. For these reasons, this variant has been classified as Pathogenic. -

Inborn genetic diseases

Pathogenic:1

Oct 24, 2023

Ambry Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.399G>A (p.M133I) alteration is located in exon 3 (coding exon 3) of the GDAP1 gene. This alteration results from a G to A substitution at nucleotide position 399, causing the methionine (M) at amino acid position 133 to be replaced by an isoleucine (I)._x000D_ _x000D_ Based on the available evidence, the c.399G>A (p.M133I) alteration alteration is classified as likely pathogenic for autosomal recessive GDAP1-related Charcot-Marie-Tooth disease; however, it is unlikely to be causative of autosomal dominant GDAP1-related Charcot-Marie-Tooth disease, type 2. Based on data from gnomAD, the A allele has an overall frequency of 0.011% (31/282872) total alleles studied. The highest observed frequency was 0.024% (31/129184) of European (non-Finnish) alleles. This alteration was detected in conjunction with another alteration in GDAP1, in multiple individuals with features consistent with GDAP1-related Charcot-Marie-Tooth disease (external communication). This amino acid position is highly conserved in available vertebrate species. This alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as likely pathogenic. -

Charcot-Marie-Tooth disease recessive intermediate A;C1842983:Charcot-Marie-Tooth disease axonal type 2K;C1843183:Charcot-Marie-Tooth disease, axonal, with vocal cord paresis, autosomal recessive;C1859198:Charcot-Marie-Tooth disease type 4A

Pathogenic:1

Jan 17, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.50

BayesDel_addAF

Pathogenic

0.26

BayesDel_noAF

Pathogenic

0.44

CADD

Uncertain

(source)

DANN

Uncertain

0.99

DEOGEN2

Benign

0.092

T;.

Eigen

Uncertain

0.27

Eigen_PC

Uncertain

0.42

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.91

D;D

M_CAP

Uncertain

0.26

MetaRNN

Uncertain

0.51

D;D

MetaSVM

Pathogenic

0.97

MutationAssessor

Benign

1.1

L;.

PhyloP100

7.7

PrimateAI

Uncertain

0.76

PROVEAN

Benign

0.35

N;N

REVEL

Uncertain

0.60

Sift

Benign

0.13

T;T

Sift4G

Uncertain

0.020

D;D

Polyphen

0.26

B;.

Vest4

0.63

MutPred

0.80

Gain of loop (P = 0.069);.;

MVP

0.98

MPC

0.48

ClinPred

0.15

GERP RS

5.5

Varity_R

0.30

gMVP

0.75

Mutation Taster

=10/90

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over