rs121912615

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 2P and 6B. PP3PP5BP4BS1_SupportingBS2

The NM_001041.4(SI):​c.1730T>G​(p.Val577Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00236 in 1,605,538 control chromosomes in the GnomAD database, including 7 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V577D) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0025 ( 7 hom. )

Consequence

SI
NM_001041.4 missense

Scores

9
6
4

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:16U:1

Conservation

PhyloP100: 8.54

Publications

18 publications found
Variant links:
Genes affected
SI (HGNC:10856): (sucrase-isomaltase) This gene encodes a sucrase-isomaltase enzyme that is expressed in the intestinal brush border. The encoded protein is synthesized as a precursor protein that is cleaved by pancreatic proteases into two enzymatic subunits sucrase and isomaltase. These two subunits heterodimerize to form the sucrose-isomaltase complex. This complex is essential for the digestion of dietary carbohydrates including starch, sucrose and isomaltose. Mutations in this gene are the cause of congenital sucrase-isomaltase deficiency.[provided by RefSeq, Apr 2010]
SI Gene-Disease associations (from GenCC):
  • congenital sucrase-isomaltase deficiency
    Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, PanelApp Australia, Labcorp Genetics (formerly Invitae), Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

PP3
Multiple lines of computational evidence support a deleterious effect 8: BayesDel_noAF, Eigen, M_CAP, MutationAssessor, phyloP100way_vertebrate, PROVEAN, REVEL, REVEL [when max_spliceai, FATHMM_MKL, MetaRNN, MutationTaster, PrimateAI was below the threshold]
PP5
Variant 3-165046998-A-C is Pathogenic according to our data. Variant chr3-165046998-A-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1418.
BP4
Computational evidence support a benign effect (MetaRNN=0.088983625). . Strength limited to SUPPORTING due to the PP5.
BS1
Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.00126 (192/152260) while in subpopulation NFE AF = 0.00212 (144/68010). AF 95% confidence interval is 0.00184. There are 0 homozygotes in GnomAd4. There are 67 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
BS2
High Homozygotes in GnomAdExome4 at 7 AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SINM_001041.4 linkc.1730T>G p.Val577Gly missense_variant Exon 16 of 48 ENST00000264382.8 NP_001032.2 P14410
SIXM_047448735.1 linkc.1730T>G p.Val577Gly missense_variant Exon 17 of 49 XP_047304691.1
SIXM_047448736.1 linkc.1730T>G p.Val577Gly missense_variant Exon 17 of 49 XP_047304692.1
SIXM_011513078.3 linkc.1631T>G p.Val544Gly missense_variant Exon 15 of 47 XP_011511380.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
SIENST00000264382.8 linkc.1730T>G p.Val577Gly missense_variant Exon 16 of 48 1 NM_001041.4 ENSP00000264382.3 P14410

Frequencies

GnomAD3 genomes
AF:
0.00126
AC:
192
AN:
152142
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000338
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000590
Gnomad ASJ
AF:
0.00346
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00104
Gnomad FIN
AF:
0.000659
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00212
Gnomad OTH
AF:
0.000479
GnomAD2 exomes
AF:
0.00160
AC:
392
AN:
244938
AF XY:
0.00158
show subpopulations
Gnomad AFR exome
AF:
0.000250
Gnomad AMR exome
AF:
0.000298
Gnomad ASJ exome
AF:
0.00299
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.000604
Gnomad NFE exome
AF:
0.00277
Gnomad OTH exome
AF:
0.00169
GnomAD4 exome
AF:
0.00248
AC:
3601
AN:
1453278
Hom.:
7
Cov.:
30
AF XY:
0.00240
AC XY:
1738
AN XY:
722932
show subpopulations
African (AFR)
AF:
0.000423
AC:
14
AN:
33126
American (AMR)
AF:
0.000296
AC:
13
AN:
43968
Ashkenazi Jewish (ASJ)
AF:
0.00306
AC:
79
AN:
25838
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39390
South Asian (SAS)
AF:
0.000839
AC:
71
AN:
84628
European-Finnish (FIN)
AF:
0.000808
AC:
43
AN:
53188
Middle Eastern (MID)
AF:
0.000525
AC:
3
AN:
5714
European-Non Finnish (NFE)
AF:
0.00294
AC:
3252
AN:
1107440
Other (OTH)
AF:
0.00210
AC:
126
AN:
59986
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.452
Heterozygous variant carriers
0
149
298
446
595
744
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
120
240
360
480
600
<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:
0.00126
AC:
192
AN:
152260
Hom.:
0
Cov.:
32
AF XY:
0.000900
AC XY:
67
AN XY:
74436
show subpopulations
African (AFR)
AF:
0.000337
AC:
14
AN:
41572
American (AMR)
AF:
0.000589
AC:
9
AN:
15268
Ashkenazi Jewish (ASJ)
AF:
0.00346
AC:
12
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5184
South Asian (SAS)
AF:
0.00104
AC:
5
AN:
4824
European-Finnish (FIN)
AF:
0.000659
AC:
7
AN:
10618
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.00212
AC:
144
AN:
68010
Other (OTH)
AF:
0.000474
AC:
1
AN:
2108
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.505
Heterozygous variant carriers
0
11
22
34
45
56
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
4
8
12
16
20
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.00223
Hom.:
1
Bravo
AF:
0.00133
TwinsUK
AF:
0.00297
AC:
11
ALSPAC
AF:
0.00234
AC:
9
ESP6500AA
AF:
0.000227
AC:
1
ESP6500EA
AF:
0.00140
AC:
12
ExAC
AF:
0.00188
AC:
228
Asia WGS
AF:
0.000866
AC:
3
AN:
3478

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:16Uncertain:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Sucrase-isomaltase deficiency Pathogenic:10
May 24, 2021
Baylor Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

-
Juno Genomics, Hangzhou Juno Genomics, Inc
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

PM2_Supporting+PM3_Strong+PP4+PP3+PS3_Moderate -

Jul 05, 2024
Aleixo Muise Laboratory, Hospital For Sick Children
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:research

PS3;PM2;PP3;PP4 -

Apr 27, 2017
Illumina Laboratory Services, Illumina
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The SI c.1730T>G (p.Val577Gly) missense variant is documented as one of the most common pathogenic variants found in individuals with congenital sucrase-isomaltase deficiency (CSID) (Gericke et al. 2016). The p.Val577Gly variant has been reported in two individual studies in which it is found in two siblings in a compound heterozygous state and in eight individual alleles of unspecified zygosity, which represented 15% of all individual alleles in the study (Sander et al. 2006; Uhrich et al. 2012). The p.Val577Gly variant was absent from the single control tested but is reported at a frequency of 0.00139 in the European American population of the Exome Sequencing Project. The Val577 residue is conserved. Functional studies performed by Alfalah et al. (2009) show that the p.Val577Gly variant results in a protein that is misfolded with a subsequent loss of enzyme activity. The variant protein was also shown to exist exclusively as a mannose-rich glycosylated species and to be retained in the endoplasmic reticulum. Based on the evidence, the p.Val577Gly variant is classified as pathogenic for congenital sucrase-isomaltase deficiency. This variant was observed by ICSL as part of a predisposition screen in an ostensibly healthy population. -

Jan 01, 2006
OMIM
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:literature only

- -

Jul 18, 2023
Revvity Omics, Revvity
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Mar 01, 2016
Division of Human Genetics, Children's Hospital of Philadelphia
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:research

- -

Oct 24, 2023
Department of Pathology and Laboratory Medicine, Sinai Health System
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:research

- -

Mar 30, 2020
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.Val577Gly (NM_001041.3 c.1730T>G) variant in SI has been reported in 2 compound heterozygous individuals with congenital sucrase-isomaltase deficiency (Sander 2006 and Haberman 2016), and segregated in 2 family members in 2 families (Sander 2006 and Haberman 2016). This variant has also been reported in ClinVar (Variation ID 1418). It has been identified in 0.3% (31/10004) of Ashkenazi Jewish and 0.3% of (342/126222) European chromosomes, including 1 homozygote, by gnomAD (https://gnomad.broadinstitute.org). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. In vitro functional studies of the p.Val577Gly variant report an impact to protein folding (Alfalah 2009). Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. In summary, this variant meets criteria to be classified as likely pathogenic for autosomal recessive congenital sucrase-isomaltase deficiency based upon biallelic occurrence in affected individuals, segregation data and functional evidence. ACMG/AMP Criteria applied: PM3_Strong, PP1, PP3, PS3_Supporting -

Jun 30, 2021
Fulgent Genetics, Fulgent Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Pathogenic:5Uncertain:1
-
Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Oct 31, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 577 of the SI protein (p.Val577Gly). This variant is present in population databases (rs121912615, gnomAD 0.3%), including at least one homozygous and/or hemizygous individual. This missense change has been observed in individual(s) with clinical features of congenital sucrase isomaltase deficiency (CSID) (PMID: 16329100, 23103650, 27749612, 28062276). It is commonly reported in individuals of European ancestry (PMID: 23103650, 28062276). ClinVar contains an entry for this variant (Variation ID: 1418). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SI protein function. Experimental studies have shown that this missense change affects SI function (PMID: 19121318). 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. -

Feb 07, 2025
GeneDx
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Published functional studies demonstrate a damaging effect with misfolding of the SI protein, preventing the protein from exiting the endoplasmic reticulum and resulting in loss of enzymatic function (PMID: 19121318, 35985447); Suggested as a possible predisposition factor for irritable bowel syndrome when seen in the heterozygous state with no second SI variant (PMID: 27872184); Observed in the homozygous state in a patient with clinical symptoms including feeding difficulties and episodic vomiting referred for genetic testing at GeneDx; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 37790351, 31589614, 27749612, 16329100, 32433684, 30609409, 32732636, 35985447, 36167617, 35753512, 27872184, 19121318, 37349966, 37951511, 36422736, 38682389, Irlayc2024[Article], 38327254) -

-
Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Aug 01, 2024
CeGaT Center for Human Genetics Tuebingen
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

SI: PM3:Strong, PM2:Supporting, PS3:Supporting -

Aug 31, 2018
Eurofins Ntd Llc (ga)
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

SI-related disorder Pathogenic:1
Apr 12, 2024
PreventionGenetics, part of Exact Sciences
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

The SI c.1730T>G variant is predicted to result in the amino acid substitution p.Val577Gly. This variant was reported in multiple individuals with autosomal recessive congenital sucrase-isomaltase deficiency (Sander et al. 2006. PubMed ID: 16329100; Uhrich et al. 2012. PubMed ID: 23103650). This variant is reported in 0.31% of alleles in individuals of Ashkenazi Jewish descent in gnomAD. This variant is interpreted as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Uncertain
0.46
BayesDel_addAF
Uncertain
0.014
T
BayesDel_noAF
Pathogenic
0.24
CADD
Uncertain
24
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.55
D
Eigen
Pathogenic
0.73
Eigen_PC
Uncertain
0.64
FATHMM_MKL
Pathogenic
1.0
D
LIST_S2
Benign
0.60
T
M_CAP
Pathogenic
0.41
D
MetaRNN
Benign
0.089
T
MetaSVM
Pathogenic
1.1
D
MutationAssessor
Pathogenic
3.2
M
PhyloP100
8.5
PrimateAI
Benign
0.48
T
PROVEAN
Pathogenic
-5.8
D
REVEL
Pathogenic
0.84
Sift
Uncertain
0.0010
D
Sift4G
Pathogenic
0.0010
D
Polyphen
1.0
D
Vest4
0.52
MVP
0.95
MPC
0.074
ClinPred
0.11
T
GERP RS
5.4
Varity_R
0.95
gMVP
0.69
Mutation Taster
=62/38
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: rs121912615; hg19: chr3-164764786; COSMIC: COSV52301193; API