rs1439582451

Variant names:

• chr4-127921925-AC-A
• rs1439582451
• NM_001371596.2:c.1036delG

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001371596.2(MFSD8):​c.1036delG​(p.Val346LeufsTer68) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000547 in 1,461,852 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: MFSD8 NM_001371596.2 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: -0.0100
• Publications: 3 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: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-127921925-AC-A is Pathogenic according to our data. Variant chr4-127921925-AC-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 464776.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.1036delG	p.Val346LeufsTer68	frameshift	Exon 10 of 12	NP_001358525.1
	MFSD8	NM_001371591.2		c.1036delG	p.Val346LeufsTer68	frameshift	Exon 10 of 12	NP_001358520.1
	MFSD8	NM_001371592.2		c.1042delG	p.Val348LeufsTer68	frameshift	Exon 10 of 12	NP_001358521.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MFSD8	ENST00000641686.2	MANE Select	c.1036delG	p.Val346LeufsTer68	frameshift	Exon 10 of 12	ENSP00000493218.2
	MFSD8	ENST00000296468.8	TSL:1	c.1036delG	p.Val346LeufsTer68	frameshift	Exon 11 of 13	ENSP00000296468.3
	MFSD8	ENST00000641186.1		c.922delG	p.Val308LeufsTer68	frameshift	Exon 9 of 11	ENSP00000493347.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251322 AF XY: 0.00

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 AF: 0.00000547 AC: 8 AN: 1461852 Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3 AN XY: 727222

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39694

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53410

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

European-Non Finnish (NFE) AF: 0.00000719 AC: 8 AN: 1112000

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Dec 19, 2018

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1036delG variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The c.1036delG variant is not observed at a significant frequency in large population cohorts (Lek et al., 2016). The c.1036delG variant causes a frameshift starting with codon Valine 346, changes this amino acid to a Leucine residue and creates a premature Stop codon at position 68 of the new reading frame, denoted p.Val346LeufsX68. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. Therefore, this variant is likely pathogenic; however, the possibility that it is benign cannot be excluded.

Neuronal ceroid lipofuscinosis 7 Pathogenic:1

Mar 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Val346Leufs*68) in the MFSD8 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MFSD8 are known to be pathogenic (PMID: 19177532, 25227500, 28586915). This variant is present in population databases (no rsID available, 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: 464776). For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.010
Mutation Taster		=4/196	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs1439582451; hg19: chr4-128843080;