rs138254713

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 4P and 13B. PM1PM5BP4_StrongBP6BS1BS2

The NM_000023.4(SGCA):​c.662G>A​(p.Arg221His) variant causes a missense change. The variant allele was found at a frequency of 0.000327 in 1,613,916 control chromosomes in the GnomAD database, including 5 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. R221P) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.00042 ( 0 hom., cov: 31)
Exomes 𝑓: 0.00032 ( 5 hom. )

Consequence

SGCA
NM_000023.4 missense

Scores

5
7
7

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:6

Conservation

PhyloP100: 4.10

Publications

12 publications found
Variant links:
Genes affected
SGCA (HGNC:10805): (sarcoglycan alpha) This gene encodes a component of the dystrophin-glycoprotein complex (DGC), which is critical to the stability of muscle fiber membranes and to the linking of the actin cytoskeleton to the extracellular matrix. Its expression is thought to be restricted to striated muscle. Mutations in this gene result in type 2D autosomal recessive limb-girdle muscular dystrophy. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2008]
SGCA Gene-Disease associations (from GenCC):
  • autosomal recessive limb-girdle muscular dystrophy
    Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
  • autosomal recessive limb-girdle muscular dystrophy type 2D
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Laboratory for Molecular Medicine, Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -9 ACMG points.

PM1
In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_000023.4
PM5
Other missense variant is known to change same aminoacid residue: Variant chr17-50169169-G-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 497670.Status of the report is reviewed_by_expert_panel, 3 stars.
BP4
Computational evidence support a benign effect (MetaRNN=0.024374247).
BP6
Variant 17-50169169-G-A is Benign according to our data. Variant chr17-50169169-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 254721.
BS1
Variant frequency is greater than expected in population eas. GnomAd4 allele frequency = 0.000421 (64/152146) while in subpopulation EAS AF = 0.0093 (48/5162). AF 95% confidence interval is 0.00721. There are 0 homozygotes in GnomAd4. There are 35 alleles in the male GnomAd4 subpopulation. Median coverage is 31. This position passed quality control check.
BS2
High Homozygotes in GnomAdExome4 at 5 AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
SGCANM_000023.4 linkc.662G>A p.Arg221His missense_variant Exon 6 of 10 ENST00000262018.8 NP_000014.1 Q16586-1A0A0S2Z4Q1
SGCANR_135553.2 linkn.698G>A non_coding_transcript_exon_variant Exon 6 of 9
SGCANM_001135697.3 linkc.584+597G>A intron_variant Intron 5 of 7 NP_001129169.1 Q16586-2A0A0S2Z4P8

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
SGCAENST00000262018.8 linkc.662G>A p.Arg221His missense_variant Exon 6 of 10 1 NM_000023.4 ENSP00000262018.3 Q16586-1

Frequencies

GnomAD3 genomes
AF:
0.000428
AC:
65
AN:
152028
Hom.:
0
Cov.:
31
show subpopulations
Gnomad AFR
AF:
0.0000966
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000655
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00947
Gnomad SAS
AF:
0.000415
Gnomad FIN
AF:
0.0000943
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000882
Gnomad OTH
AF:
0.000957
GnomAD2 exomes
AF:
0.000581
AC:
146
AN:
251320
AF XY:
0.000530
show subpopulations
Gnomad AFR exome
AF:
0.000123
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00707
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000791
Gnomad OTH exome
AF:
0.000163
GnomAD4 exome
AF:
0.000317
AC:
463
AN:
1461770
Hom.:
5
Cov.:
32
AF XY:
0.000322
AC XY:
234
AN XY:
727190
show subpopulations
African (AFR)
AF:
0.000179
AC:
6
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26134
East Asian (EAS)
AF:
0.00793
AC:
315
AN:
39700
South Asian (SAS)
AF:
0.000243
AC:
21
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53356
Middle Eastern (MID)
AF:
0.000173
AC:
1
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000899
AC:
100
AN:
1111964
Other (OTH)
AF:
0.000331
AC:
20
AN:
60392
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.487
Heterozygous variant carriers
0
29
57
86
114
143
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
10
20
30
40
50
<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:
0.000421
AC:
64
AN:
152146
Hom.:
0
Cov.:
31
AF XY:
0.000471
AC XY:
35
AN XY:
74388
show subpopulations
African (AFR)
AF:
0.0000964
AC:
4
AN:
41510
American (AMR)
AF:
0.0000654
AC:
1
AN:
15286
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00930
AC:
48
AN:
5162
South Asian (SAS)
AF:
0.000415
AC:
2
AN:
4816
European-Finnish (FIN)
AF:
0.0000943
AC:
1
AN:
10600
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000883
AC:
6
AN:
67984
Other (OTH)
AF:
0.000947
AC:
2
AN:
2112
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.502
Heterozygous variant carriers
0
4
9
13
18
22
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome 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
Alfa
AF:
0.000448
Hom.:
0
Bravo
AF:
0.000518
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000465
AC:
4
ExAC
AF:
0.000593
AC:
72
Asia WGS
AF:
0.00520
AC:
18
AN:
3478
EpiCase
AF:
0.0000545
EpiControl
AF:
0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:4Benign:6
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2D Uncertain:3Benign:1
May 18, 2021
Genome-Nilou Lab
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Feb 08, 2017
Counsyl
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Jan 29, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Apr 03, 2020
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

not specified Benign:3
May 23, 2017
Eurofins Ntd Llc (ga)
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

-
PreventionGenetics, part of Exact Sciences
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Aug 19, 2022
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: SGCA c.662G>A (p.Arg221His) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00058 in 251320 control chromosomes, predominantly at a frequency of 0.0071 within the East Asian subpopulation in the gnomAD database, including 2 homozygotes. The observed variant frequency within East Asian control individuals in the gnomAD database is approximately 3-fold of the estimated maximal expected allele frequency for a pathogenic variant in SGCA causing Limb-Girdle Muscular Dystrophy (LGMD), Autosomal Recessive phenotype (0.002), strongly suggesting that the variant is a benign polymorphism found primarily in populations of East Asian origin. c.662G>A has been reported in the literature in individuals affected with Limb-Girdle Muscular Dystrophy with little evidence for causality and/or in individuals with a very mild phenotype (e.g. Boito_2003, Tian_2015, Yu_2017, Xie_2019). These report(s) do not provide unequivocal conclusions about association of the variant with Limb-Girdle Muscular Dystrophy. At-least one co-occurrence with another homozygous pathogenic variant have been reported in an individual with LGMD (DYSF exon 5 deletion), providing supporting evidence for a benign role (example, Tian_2015). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Eight submitters have provided clinical-significance assessments for this variant to ClinVar after 2014 with conflicting assessments(VUS n=4, likely benign n=3, benign n=1). Based on the evidence outlined above, the variant was classified as likely benign. -

not provided Uncertain:1Benign:1
Apr 13, 2020
Mayo Clinic Laboratories, Mayo Clinic
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jan 11, 2019
GeneDx
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 12746421, 24742800, 19117361) -

Sarcoglycanopathy Benign:1
Apr 27, 2017
Illumina Laboratory Services, Illumina
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. The evidence from the literature, in combination with allele frequency data from public databases where available, was sufficient to determine this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.14
BayesDel_addAF
Uncertain
0.033
T
BayesDel_noAF
Pathogenic
0.28
CADD
Pathogenic
27
DANN
Pathogenic
1.0
DEOGEN2
Uncertain
0.77
D
Eigen
Uncertain
0.64
Eigen_PC
Uncertain
0.61
FATHMM_MKL
Uncertain
0.85
D
LIST_S2
Benign
0.80
T
M_CAP
Pathogenic
0.34
D
MetaRNN
Benign
0.024
T
MetaSVM
Pathogenic
0.93
D
MutationAssessor
Uncertain
2.5
M
PhyloP100
4.1
PrimateAI
Benign
0.48
T
PROVEAN
Benign
-1.2
N
REVEL
Pathogenic
0.78
Sift
Benign
0.050
D
Sift4G
Uncertain
0.022
D
Polyphen
1.0
D
Vest4
0.26
MVP
0.99
MPC
0.88
ClinPred
0.057
T
GERP RS
5.1
Varity_R
0.091
gMVP
0.65
Mutation Taster
=79/21
polymorphism

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

Publications

Other links and lift over

dbSNP: rs138254713; hg19: chr17-48246530; COSMIC: COSV56248791; COSMIC: COSV56248791; API