4-127943829-T-G

Variant names:

• chr4-127943829-T-G
• rs118203978
• NM_001371596.2:c.362A>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PM5 PP3_Moderate

The NM_001371596.2(MFSD8):​c.362A>C​(p.Tyr121Ser) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. Y121C) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MFSD8 NM_001371596.2 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.02
• Publications: 7 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: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr4-127943829-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1004.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.929

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001371596.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MFSD8	NM_001371596.2	MANE Select	c.362A>C	p.Tyr121Ser	missense	Exon 4 of 12	NP_001358525.1
	MFSD8	NM_001371591.2		c.362A>C	p.Tyr121Ser	missense	Exon 4 of 12	NP_001358520.1
	MFSD8	NM_001371592.2		c.362A>C	p.Tyr121Ser	missense	Exon 4 of 12	NP_001358521.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MFSD8	ENST00000641686.2	MANE Select	c.362A>C	p.Tyr121Ser	missense	Exon 4 of 12	ENSP00000493218.2
	MFSD8	ENST00000296468.8	TSL:1	c.362A>C	p.Tyr121Ser	missense	Exon 5 of 13	ENSP00000296468.3
	MFSD8	ENST00000641186.1		c.362A>C	p.Tyr121Ser	missense	Exon 4 of 11	ENSP00000493347.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251318 AF XY: 0.00000736

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: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neuronal ceroid lipofuscinosis 7 Uncertain:1

Oct 14, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tyrosine, which is neutral and polar, with serine, which is neutral and polar, at codon 121 of the MFSD8 protein (p.Tyr121Ser). This variant is present in population databases (rs118203978, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with MFSD8-related conditions. ClinVar contains an entry for this variant (Variation ID: 934468). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt MFSD8 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 v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.70
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.47	T
Eigen	Uncertain	0.67
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.97	D
M_CAP	Uncertain	0.14	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Uncertain	-0.18	T
MutationAssessor	Pathogenic	3.2	M
PhyloP100		7.0
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-8.3	D
REVEL	Uncertain	0.64
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.81		Gain of catalytic residue at Y121 (P = 0.1729)
MVP		0.77
MPC		0.59
ClinPred		1.0	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.93
gMVP		0.87
Mutation Taster		=11/89	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs118203978; hg19: chr4-128864984;