17-50167431-G-T

Variant names:

• chr17-50167431-G-T
• rs371675217
• NM_000023.4:c.101G>T

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1 PM2 PM5 PP3

The NM_000023.4(SGCA):​c.101G>T​(p.Arg34Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,874 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R34C) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SGCA NM_000023.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.900
• Publications: 20 publications found

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, STRONG Submitted by: ClinGen, PanelApp Australia
• autosomal recessive limb-girdle muscular dystrophy type 2D

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Myriad Women’s Health, Labcorp Genetics (formerly Invitae), Orphanet

ENSG00000253730 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 5 uncertain in NM_000023.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-50167430-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 217250.Status of the report is reviewed_by_expert_panel, 3 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.791

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000023.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SGCA	NM_000023.4	MANE Select	c.101G>T	p.Arg34Leu	missense	Exon 2 of 10	NP_000014.1	A0A0S2Z4Q1
	SGCA	NM_001135697.3		c.101G>T	p.Arg34Leu	missense	Exon 2 of 8	NP_001129169.1	A0A0S2Z4P8
	SGCA	NR_135553.2		n.137G>T		non_coding_transcript_exon	Exon 2 of 9

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SGCA	ENST00000262018.8	TSL:1 MANE Select	c.101G>T	p.Arg34Leu	missense	Exon 2 of 10	ENSP00000262018.3	Q16586-1
	SGCA	ENST00000344627.10	TSL:1	c.101G>T	p.Arg34Leu	missense	Exon 2 of 8	ENSP00000345522.6	Q16586-2
	SGCA	ENST00000952408.1		c.191G>T	p.Arg64Leu	missense	Exon 2 of 10	ENSP00000622467.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251430 AF XY: 0.00000736

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461874 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727240

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

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: 39700

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

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: 0.00 AC: 0 AN: 1112004

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.18
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Pathogenic	0.21
CADD	Benign	18
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.73	D
Eigen	Benign	-0.18
Eigen_PC	Benign	-0.079
FATHMM_MKL	Uncertain	0.79	D
LIST_S2	Benign	0.84	T
M_CAP	Pathogenic	0.36	D
MetaRNN	Pathogenic	0.79	D
MetaSVM	Pathogenic	0.81	D
MutationAssessor	Uncertain	2.3	M
PhyloP100		0.90
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-0.44	N
REVEL	Uncertain	0.64
Sift	Benign	0.15	T
Sift4G	Benign	0.16	T
Polyphen		0.22	B
Vest4		0.48
MutPred		0.78		Loss of methylation at R34 (P = 0.0204)
MVP		0.98
MPC		0.45
ClinPred		0.74	D
GERP RS		4.5
Varity_R		0.10
gMVP		0.79
Mutation Taster		=4/96	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs371675217; hg19: chr17-48244792; COSMIC: COSV56249347; COSMIC: COSV56249347;