rs139732572

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 5P and 4B. PVS1_StrongPP5BS2

The NM_000146.4(FTL):​c.1A>G​(p.Met1?) variant causes a start lost change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000118 in 1,612,424 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

FTL
NM_000146.4 start_lost

Scores

5
9
2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:3

Conservation

PhyloP100: 8.51

Publications

3 publications found
Variant links:
Genes affected
FTL (HGNC:3999): (ferritin light chain) This gene encodes the light subunit of the ferritin protein. Ferritin is the major intracellular iron storage protein in prokaryotes and eukaryotes. It is composed of 24 subunits of the heavy and light ferritin chains. Variation in ferritin subunit composition may affect the rates of iron uptake and release in different tissues. A major function of ferritin is the storage of iron in a soluble and nontoxic state. Defects in this light chain ferritin gene are associated with several neurodegenerative diseases and hyperferritinemia-cataract syndrome. This gene has multiple pseudogenes. [provided by RefSeq, Jul 2008]
FTL Gene-Disease associations (from GenCC):
  • hereditary hyperferritinemia with congenital cataracts
    Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Orphanet
  • neuroferritinopathy
    Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet
  • L-ferritin deficiency
    Inheritance: Unknown, AD Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet
  • genetic hyperferritinemia without iron overload
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PVS1
Start lost variant, next in-frame start position is after 4 pathogenic variants. Next in-frame start position is after 69 codons. Genomic position: 48965872. Lost 0.388 part of the original CDS.
PP5
Variant 19-48965508-A-G is Pathogenic according to our data. Variant chr19-48965508-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 96689.
BS2
High AC in GnomAdExome4 at 17 Unknown,AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
FTLNM_000146.4 linkc.1A>G p.Met1? start_lost Exon 1 of 4 ENST00000331825.11 NP_000137.2 P02792A0A384MDR3

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
FTLENST00000331825.11 linkc.1A>G p.Met1? start_lost Exon 1 of 4 1 NM_000146.4 ENSP00000366525.2 P02792

Frequencies

GnomAD3 genomes
AF:
0.0000131
AC:
2
AN:
152140
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.000478
GnomAD2 exomes
AF:
0.0000119
AC:
3
AN:
251104
AF XY:
0.00000737
show subpopulations
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:
0.0000264
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000116
AC:
17
AN:
1460284
Hom.:
0
Cov.:
30
AF XY:
0.0000124
AC XY:
9
AN XY:
726578
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33448
American (AMR)
AF:
0.00
AC:
0
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26122
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39692
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86224
European-Finnish (FIN)
AF:
0.0000189
AC:
1
AN:
53046
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5602
European-Non Finnish (NFE)
AF:
0.00000990
AC:
11
AN:
1111102
Other (OTH)
AF:
0.0000332
AC:
2
AN:
60328
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.466
Heterozygous variant carriers
0
1
2
3
4
5
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000131
AC:
2
AN:
152140
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74334
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
41444
American (AMR)
AF:
0.00
AC:
0
AN:
15266
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5184
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10610
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68016
Other (OTH)
AF:
0.000478
AC:
1
AN:
2094
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.400
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.0000198
Hom.:
0
Bravo
AF:
0.0000189
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000116
AC:
1
ExAC
AF:
0.00000824
AC:
1
EpiCase
AF:
0.00
EpiControl
AF:
0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:2Uncertain:3
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

L-ferritin deficiency Pathogenic:1Uncertain:1
Jun 01, 2004
OMIM
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Jan 25, 2023
Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:curation

The heterozygous p.Met1Val variant in FTL was identified by our study in one individual with low serum ferritin. The p.Met1Val variant in FTL has been reported in 2 unrelated individuals with autosomal dominant L-ferritin deficiency (PMID: 30678075, PMID: 15173247) and segregated with disease in 2 affective relatives from one family (PMID: 30678075), but has been identified in 0.003% (3/113706) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs139732572). Although this variant has been seen in the general population in a heterozygous state, its frequency is not high enough to rule out a pathogenic role. Pathogenic variants may be present at a low frequency in the general population, for diseases with clinical variability, or reduced penetrance. This variant has also been reported in ClinVar (Variation ID: 96689) and has been interpreted as pathogenic by OMIM, as likely pathogenic by LabCorp, and as a variant of uncertain significance by Invitae. This variant is located in the first amino acid and obliterates the methionine initiation codon. The next in-frame methionine is at amino acid residue 69 and there are 2 reported pathogenic or likely pathogenic variants in ClinVar upstream of this downstream methionine. It is of note that loss of function of FTL in an autosomal dominant disease has not yet been established based on the criteria laid out in Tayoun et al., 2018 (PMID: 30192042). In summary, the clinical significance of the p.Met1Val variant is uncertain. ACMG/AMP Criteria applied: PS4_Supporting (Richards 2015). -

not provided Pathogenic:1
Jan 01, 2024
CeGaT Center for Human Genetics Tuebingen
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

FTL: PM2, PS4:Moderate, PVS1:Moderate, PP1, PP4 -

not specified Uncertain:1
Apr 25, 2024
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: FTL c.1A>G (p.Met1Val) alters the initiation codon and is predicted to result either in absence of the protein or truncation of the encoded protein due to translation initiation at a downstream codon. An alternative downstream in-frame start codon (Met69) is located in the encoded protein. Two of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 1.2e-05 in 251104 control chromosomes. c.1A>G has been reported in the literature in at least two heterozygous individuals affected with autosomal dominant L-Ferritin Deficiency (e.g. Cremonesi_2004, Cadenas_2019). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 30678075, 15173247). ClinVar contains an entry for this variant (Variation ID: 96689). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Hereditary hyperferritinemia with congenital cataracts;C1853578:Neuroferritinopathy Uncertain:1
Aug 28, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change affects the initiator methionine of the FTL mRNA. The next in-frame methionine is located at codon 69. This variant is present in population databases (rs139732572, gnomAD 0.003%). Disruption of the initiator codon has been observed in individual(s) with L-ferritin deficiency (PMID: 15173247, 30678075). ClinVar contains an entry for this variant (Variation ID: 96689). 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
BayesDel_addAF
Pathogenic
0.31
D
BayesDel_noAF
Pathogenic
0.28
CADD
Uncertain
24
DANN
Uncertain
0.99
DEOGEN2
Uncertain
0.55
D
Eigen
Uncertain
0.25
Eigen_PC
Uncertain
0.37
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Uncertain
0.90
D
M_CAP
Pathogenic
0.70
D
MetaRNN
Pathogenic
0.87
D
MetaSVM
Benign
-0.58
T
PhyloP100
8.5
PROVEAN
Uncertain
-2.6
D
REVEL
Uncertain
0.54
Sift
Uncertain
0.015
D
Sift4G
Uncertain
0.053
T
Polyphen
0.11
B
Vest4
0.93
MVP
0.70
ClinPred
0.90
D
GERP RS
5.5
PromoterAI
-0.0086
Neutral
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.40
gMVP
0.25
Mutation Taster
=17/183
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.010
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs139732572; hg19: chr19-49468765; COSMIC: COSV53171537; COSMIC: COSV53171537; API