Genetic Variant MFSD8:p.Ala423Gly (chr4-127921606-G-C) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2PP3_Moderate

The NM_001371596.2(MFSD8):c.1268C>G(p.Ala423Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,872 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/24 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A423V) has been classified as Benign.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MFSD8
NM_001371596.2 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 1.52

Publications

1 publications found

Variant links:

Genes affected

MFSD8 (HGNC:28486): (major facilitator superfamily domain containing 8) This gene encodes a ubiquitous integral membrane protein that contains a transporter domain and a major facilitator superfamily (MFS) domain. Other members of the major facilitator superfamily transport small solutes through chemiosmotic ion gradients. The substrate transported by this protein is unknown. The protein likely localizes to lysosomal membranes. Mutations in this gene are correlated with a variant form of late infantile-onset neuronal ceroid lipofuscinoses (vLINCL). [provided by RefSeq, Oct 2008]

MFSD8 Gene-Disease associations (from GenCC):

neuronal ceroid lipofuscinosis
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
neuronal ceroid lipofuscinosis 7
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet, G2P
macular dystrophy with central cone involvement
Inheritance: AR Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)

MFSD8 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

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

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MFSD8	NM_001371596.2 link	c.1268C>G	p.Ala423Gly	missense_variant	Exon 11 of 12	ENST00000641686.2	NP_001358525.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MFSD8	ENST00000641686.2 link	c.1268C>G	p.Ala423Gly	missense_variant	Exon 11 of 12		NM_001371596.2	ENSP00000493218.2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461872

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727232

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112008

Other (OTH)

AF:

0.00

AC:

AN:

60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Benign

-0.11

BayesDel_noAF

Benign

-0.39

CADD

Benign

(source)

DANN

Benign

0.90

DEOGEN2

Benign

0.056

T;T;.;.;.;.;.;.;.;.

Eigen

Benign

-0.93

Eigen_PC

Benign

-0.89

FATHMM_MKL

Uncertain

0.76

LIST_S2

Uncertain

0.89

.;.;D;D;D;.;D;D;D;D

M_CAP

Benign

0.043

MetaRNN

Benign

0.28

T;T;T;T;T;T;T;T;T;T

MetaSVM

Benign

-0.91

MutationAssessor

Uncertain

2.3

M;M;.;.;.;.;.;.;.;.

PhyloP100

1.5

PrimateAI

Benign

0.30

PROVEAN

Benign

-1.3

.;N;.;.;.;.;.;.;.;.

REVEL

Benign

0.15

Sift

Benign

0.34

.;T;.;.;.;.;.;.;.;.

Sift4G

Benign

0.38

.;T;.;.;.;.;.;.;.;.

Polyphen

0.11

B;B;.;.;.;.;.;.;.;.

Vest4

0.20

MutPred

0.66

Loss of stability (P = 0.0427);Loss of stability (P = 0.0427);.;.;.;.;.;.;.;Loss of stability (P = 0.0427);

MVP

0.50

MPC

0.12

ClinPred

0.20

GERP RS

0.14

Varity_R

0.025

gMVP

0.70

Mutation Taster

=90/10

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.97

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.97

Position offset: 1

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

ClinVar

Computational scores

Splicing

Publications

Other links and lift over