chr1-21847391-G-C

Variant names:

• chr1-21847391-G-C
• rs547310973
• NM_005529.7:c.8127C>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_005529.7(HSPG2):​c.8127C>G​(p.Ile2709Met) 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 1,461,650 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. I2709I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: HSPG2 NM_005529.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.0210
• Publications: 1 publications found

Genes affected

HSPG2 (HGNC:5273): (heparan sulfate proteoglycan 2) This gene encodes the perlecan protein, which consists of a core protein to which three long chains of glycosaminoglycans (heparan sulfate or chondroitin sulfate) are attached. The perlecan protein is a large multidomain proteoglycan that binds to and cross-links many extracellular matrix components and cell-surface molecules. It has been shown that this protein interacts with laminin, prolargin, collagen type IV, FGFBP1, FBLN2, FGF7 and transthyretin, etc., and it plays essential roles in multiple biological activities. Perlecan is a key component of the vascular extracellular matrix, where it helps to maintain the endothelial barrier function. It is a potent inhibitor of smooth muscle cell proliferation and is thus thought to help maintain vascular homeostasis. It can also promote growth factor (e.g., FGF2) activity and thus stimulate endothelial growth and re-generation. It is a major component of basement membranes, where it is involved in the stabilization of other molecules as well as being involved with glomerular permeability to macromolecules and cell adhesion. Mutations in this gene cause Schwartz-Jampel syndrome type 1, Silverman-Handmaker type of dyssegmental dysplasia, and tardive dyskinesia. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2014]

HSPG2 Gene-Disease associations (from GenCC):

• Schwartz-Jampel syndrome type 1

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P
• Silverman-Handmaker type dyssegmental dysplasia

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, ClinGen, Labcorp Genetics (formerly Invitae)
• Schwartz-Jampel syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005529.7. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HSPG2	NM_005529.7	MANE Select	c.8127C>G	p.Ile2709Met	missense	Exon 62 of 97	NP_005520.4
	HSPG2	NM_001291860.2		c.8130C>G	p.Ile2710Met	missense	Exon 62 of 97	NP_001278789.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HSPG2	ENST00000374695.8	TSL:1 MANE Select	c.8127C>G	p.Ile2709Met	missense	Exon 62 of 97	ENSP00000363827.3
	HSPG2	ENST00000453796.1	TSL:2	n.372C>G		non_coding_transcript_exon	Exon 2 of 4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251328 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

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: 1461650 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727144

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

American (AMR) AF: 0.0000224 AC: 1 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53202

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111990

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Jun 24, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.8127C>G (p.I2709M) alteration is located in exon 61 (coding exon 61) of the HSPG2 gene. This alteration results from a C to G substitution at nucleotide position 8127, causing the isoleucine (I) at amino acid position 2709 to be replaced by a methionine (M). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.37
CADD	Benign	14
DANN	Uncertain	0.99
DEOGEN2	Benign	0.31	T
Eigen	Benign	-0.11
Eigen_PC	Benign	-0.30
FATHMM_MKL	Benign	0.24	N
LIST_S2	Benign	0.72	T
M_CAP	Uncertain	0.090	D
MetaRNN	Uncertain	0.47	T
MetaSVM	Benign	-0.59	T
MutationAssessor	Uncertain	2.1	M
PhyloP100		-0.021
PrimateAI	Uncertain	0.49	T
PROVEAN	Benign	-1.4	N
REVEL	Benign	0.22
Sift	Benign	0.037	D
Sift4G	Uncertain	0.0080	D
Polyphen		1.0	D
Vest4		0.41
MutPred		0.46		Gain of sheet (P = 0.039)
MVP		0.65
MPC		0.67
ClinPred		0.38	T
GERP RS		1.4
Varity_R		0.095
gMVP		0.29
Mutation Taster		=96/4	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs547310973; hg19: chr1-22173884;