2-219551566-G-A

Variant names:

• chr2-219551566-G-A
• rs373603020
• NM_015311.3:c.5646C>T

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_015311.3(OBSL1):​c.5646C>T​(p.Ala1882Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000345 in 1,450,572 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. A1882A) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: OBSL1 NM_015311.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.939
• Publications: 0 publications found

Genes affected

OBSL1 (HGNC:29092): (obscurin like cytoskeletal adaptor 1) Cytoskeletal adaptor proteins function in linking the internal cytoskeleton of cells to the cell membrane. This gene encodes a cytoskeletal adaptor protein, which is a member of the Unc-89/obscurin family. The protein contains multiple N- and C-terminal immunoglobulin (Ig)-like domains and a central fibronectin type 3 domain. Mutations in this gene cause 3M syndrome type 2. Alternatively spliced transcript variants encoding different isoforms have been found in this gene. [provided by RefSeq, Mar 2010]

OBSL1 Gene-Disease associations (from GenCC):

• 3M syndrome 2

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
• 3-M syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.57).
• BP7: Synonymous conserved (PhyloP=-0.939 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_015311.3. 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
	OBSL1	NM_015311.3	MANE Select	c.5646C>T	p.Ala1882Ala	synonymous	Exon 20 of 21	NP_056126.1	O75147-3

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	OBSL1	ENST00000404537.6	TSL:1 MANE Select	c.5646C>T	p.Ala1882Ala	synonymous	Exon 20 of 21	ENSP00000385636.1	O75147-3
	OBSL1	ENST00000953546.1		c.5658C>T	p.Ala1886Ala	synonymous	Exon 20 of 21	ENSP00000623605.1
	OBSL1	ENST00000953548.1		c.5589C>T	p.Ala1863Ala	synonymous	Exon 20 of 21	ENSP00000623607.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000876 AC: 2 AN: 228374 AF XY: 0.00000806

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000307

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: 0.00000345 AC: 5 AN: 1450572 Hom.: 0 Cov.: 33 AF XY: 0.00000278 AC XY: 2 AN XY: 720414

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

African (AFR) AF: 0.0000300 AC: 1 AN: 33282

American (AMR) AF: 0.0000231 AC: 1 AN: 43266

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25860

East Asian (EAS) AF: 0.00 AC: 0 AN: 39142

South Asian (SAS) AF: 0.0000119 AC: 1 AN: 84080

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52312

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5742

European-Non Finnish (NFE) AF: 0.00000181 AC: 2 AN: 1106942

Other (OTH) AF: 0.00 AC: 0 AN: 59946

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00353856), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.57
CADD	Benign	5.1
DANN	Benign	0.86
PhyloP100		-0.94
Mutation Taster		=100/0	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs373603020; hg19: chr2-220416288;