rs878855229

chr4-127920758-C-T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001371596.2(MFSD8):c.1429G>A(p.Ala477Thr) 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 1,461,860 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. A477A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MFSD8 NM_001371596.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 2.11

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]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.037641585).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MFSD8	NM_001371596.2	c.1429G>A	p.Ala477Thr	missense_variant	12/12	ENST00000641686.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MFSD8	ENST00000641686.2	c.1429G>A	p.Ala477Thr	missense_variant	12/12		NM_001371596.2	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461860 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727234

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

Late-infantile neuronal ceroid lipofuscinosis Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Jul 10, 2020

- -

Neuronal ceroid lipofuscinosis 7 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 30, 2021

This sequence change replaces alanine with threonine at codon 477 of the MFSD8 protein (p.Ala477Thr). The alanine residue is weakly conserved and there is a small physicochemical difference between alanine and threonine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with MFSD8-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The threonine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.065
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.53
Cadd	Benign	10
Dann	Benign	0.28
DEOGEN2	Benign	0.027	T;T;.;.;.;.;.;.;.
Eigen	Benign	-1.0
Eigen_PC	Benign	-0.81
FATHMM_MKL	Benign	0.29	N
M_CAP	Benign	0.0049	T
MetaRNN	Benign	0.038	T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.95	T
MutationAssessor	Benign	-2.1	N;N;.;.;.;.;.;.;.
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.28	T
Polyphen		0.0	B;B;.;.;.;.;.;.;.
Vest4		0.061
MutPred		0.40		Gain of helix (P = 0.0143);Gain of helix (P = 0.0143);.;.;.;.;.;.;.;
MVP		0.26
MPC		0.091
ClinPred		0.23	T
GERP RS		-1.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.028
gMVP		0.18

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

Publications

LitVar

Other links and lift over

dbSNP: rs878855229; hg19: chr4-128841913;