9-127454489-G-GC

Variant names:

• chr9-127454489-G-GC
• rs1176611059
• NM_001005373.4:c.-32-3dupC

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PVS1_Moderate

The NM_001005373.4(LRSAM1):​c.-32-3dupC variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000559 in 1,610,190 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: LRSAM1 NM_001005373.4 splice_acceptor, intron
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.529
• Publications: 0 publications found

Genes affected

LRSAM1 (HGNC:25135): (leucine rich repeat and sterile alpha motif containing 1) This gene encodes a ring finger protein involved in a variety of functions, including regulation of signaling pathways and cell adhesion, mediation of self-ubiquitylation, and involvement in cargo sorting during receptor endocytosis. Mutations in this gene have been associated with Charcot-Marie-Tooth disease. Multiple transcript variants encoding different isoforms have been identified for this gene. [provided by RefSeq, Jan 2012]

LRSAM1 Gene-Disease associations (from GenCC):

• Charcot-Marie-Tooth disease axonal type 2P

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen

ACMG classification

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

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.047882136 fraction of the gene. Cryptic splice site detected, with MaxEntScore 11, offset of 0 (no position change), new splice context is: cttctctcctgtgcccccAGggt. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LRSAM1	NM_001005373.4	c.-32-3dupC		splice_acceptor_variant, intron_variant	Intron 2 of 25	ENST00000300417.11	NP_001005373.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LRSAM1	ENST00000300417.11	c.-32-3dupC		splice_acceptor_variant, intron_variant	Intron 2 of 25	1	NM_001005373.4	ENSP00000300417.6

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152204 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000549 AC: 8 AN: 1457986 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 725536

African (AFR) AF: 0.00 AC: 0 AN: 33408

American (AMR) AF: 0.00 AC: 0 AN: 44598

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26096

East Asian (EAS) AF: 0.00 AC: 0 AN: 39682

South Asian (SAS) AF: 0.00 AC: 0 AN: 86022

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53384

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 0.00000722 AC: 8 AN: 1108766

Other (OTH) AF: 0.00 AC: 0 AN: 60270

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152204 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74358

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 41440

American (AMR) AF: 0.0000655 AC: 1 AN: 15276

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5202

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10624

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68034

Other (OTH) AF: 0.00 AC: 0 AN: 2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Charcot-Marie-Tooth disease axonal type 2P Uncertain:1

Nov 08, 2023

Clinical Genomics Laboratory, Washington University in St. Louis

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The LRSAM1 c.-32-3dup intronic variant, to our knowledge, has not been reported in the medical literature and is absent from the general population (gnomAD v.2.1.1), indicating it is not a common variant. Computational predictors indicate that the variant has no impact on splicing, evidence that this variant does not have a damaging effect on LRSAM1 function. Due to limited information, and based on ACMG/AMP guidelines for variant interpretation (Richards S et al., PMID: 25741868), the clinical significance of this variant is uncertain at this time. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.53

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: rs1176611059; hg19: chr9-130216768;