rs1374593138

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1PM2PP5

The NM_015166.4(MLC1):​c.177+1G>T variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.0000031 in 1,613,750 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)
Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

MLC1
NM_015166.4 splice_donor, intron

Scores

4
2
Splicing: ADA: 1.000
2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:6U:1

Conservation

PhyloP100: 6.89

Publications

3 publications found
Variant links:
Genes affected
MLC1 (HGNC:17082): (modulator of VRAC current 1) The function of this gene product is unknown; however, homology to other proteins suggests that it may be an integral membrane transporter. Mutations in this gene have been associated with megalencephalic leukoencephalopathy with subcortical cysts, an autosomal recessive neurological disorder. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008]
MLC1 Gene-Disease associations (from GenCC):
  • megalencephalic leukoencephalopathy with subcortical cysts 1
    Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P, Myriad Women’s Health
  • megalencephalic leukoencephalopathy with subcortical cysts
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3.5, offset of -25, new splice context is: gacGTgggt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 22-50084725-C-A is Pathogenic according to our data. Variant chr22-50084725-C-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 548493.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_015166.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
MLC1
NM_015166.4
MANE Select
c.177+1G>T
splice_donor intron
N/ANP_055981.1
MLC1
NM_001376472.1
c.177+1G>T
splice_donor intron
N/ANP_001363401.1
MLC1
NM_001376473.1
c.177+1G>T
splice_donor intron
N/ANP_001363402.1

Ensembl Transcripts

Selected
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
MLC1
ENST00000311597.10
TSL:1 MANE Select
c.177+1G>T
splice_donor intron
N/AENSP00000310375.6
MLC1
ENST00000395876.6
TSL:1
c.177+1G>T
splice_donor intron
N/AENSP00000379216.2
MLC1
ENST00000442311.1
TSL:5
c.177+1G>T
splice_donor intron
N/AENSP00000401385.1

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152242
Hom.:
0
Cov.:
33
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:
0.00
GnomAD4 exome
AF:
0.00000274
AC:
4
AN:
1461508
Hom.:
0
Cov.:
32
AF XY:
0.00000275
AC XY:
2
AN XY:
727058
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33476
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26134
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39698
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86244
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53326
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5636
European-Non Finnish (NFE)
AF:
0.00000360
AC:
4
AN:
1111902
Other (OTH)
AF:
0.00
AC:
0
AN:
60368
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152242
Hom.:
0
Cov.:
33
AF XY:
0.00
AC XY:
0
AN XY:
74370
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41464
American (AMR)
AF:
0.00
AC:
0
AN:
15284
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5200
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10626
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68048
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
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:
0.00
Hom.:
0
Bravo
AF:
0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:6Uncertain:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Megalencephalic leukoencephalopathy with subcortical cysts 1 Pathogenic:3
Apr 24, 2025
Institute of Medical Genetics and Applied Genomics, University Hospital Tübingen
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Mar 20, 2025
Revvity Omics, Revvity
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Oct 16, 2023
Baylor Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Megalencephalic leukoencephalopathy with subcortical cysts Pathogenic:1Uncertain:1
May 08, 2025
Natera, Inc.
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

Mar 05, 2018
Genomic Research Center, Shahid Beheshti University of Medical Sciences
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

not provided Pathogenic:1
May 05, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with megalencephalic leukoencephalopathy with subcortical cysts (PMID: 12939431, 27264811). ClinVar contains an entry for this variant (Variation ID: 548493). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. This sequence change affects a donor splice site in intron 2 of the MLC1 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in MLC1 are known to be pathogenic (PMID: 11254442, 16470554, 24824219).

Abnormality of the nervous system Pathogenic:1
Jul 10, 2021
Kariminejad - Najmabadi Pathology & Genetics Center
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.63
D
BayesDel_noAF
Pathogenic
0.38
CADD
Pathogenic
35
DANN
Uncertain
1.0
Eigen
Pathogenic
1.2
Eigen_PC
Pathogenic
1.0
FATHMM_MKL
Uncertain
0.94
D
PhyloP100
6.9
GERP RS
5.5
Mutation Taster
=0/100
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.94
SpliceAI score (max)
1.0
Details are displayed if max score is > 0.2
DS_DG_spliceai
0.56
Position offset: 26
DS_DL_spliceai
1.0
Position offset: 1

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

Publications

Other links and lift over

dbSNP: rs1374593138; hg19: chr22-50523154; API