rs878855229

Variant names:

• chr4-127920758-C-T
• rs878855229
• NM_001371596.2:c.1429G>A

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 4P and 4B. PM1 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. 17/22 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
• Publications: 1 publications found

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)

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 11 uncertain in NM_001371596.2
• 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 rank	MANE	Protein	UniProt
MFSD8	NM_001371596.2	c.1429G>A	p.Ala477Thr	missense_variant	Exon 12 of 12	ENST00000641686.2	NP_001358525.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MFSD8	ENST00000641686.2	c.1429G>A	p.Ala477Thr	missense_variant	Exon 12 of 12		NM_001371596.2	ENSP00000493218.2

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

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53406

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111998

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

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

Jul 10, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Neuronal ceroid lipofuscinosis 7 Uncertain:1

Aug 30, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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
LIST_S2	Uncertain	0.88	.;.;D;D;D;.;D;D;D
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;.;.;.;.;.;.;.
PhyloP100		2.1
PrimateAI	Benign	0.28	T
PROVEAN	Benign	2.1	.;N;.;.;.;.;.;.;.
REVEL	Benign	0.11
Sift	Benign	1.0	.;T;.;.;.;.;.;.;.
Sift4G	Benign	1.0	.;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
Mutation Taster		=83/17	polymorphism

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: rs878855229; hg19: chr4-128841913;