2-219570312-A-GG

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_015311.3(OBSL1):c.921delinsCC(p.Tyr308LeufsTer47) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. L307L) has been classified as Benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 35)
• Consequence: OBSL1 NM_015311.3 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: -0.333

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]

INHA (HGNC:6065): (inhibin subunit alpha) This gene encodes a member of the TGF-beta (transforming growth factor-beta) superfamily of proteins. The encoded preproprotein is proteolytically processed to generate multiple peptide products, including the alpha subunit of the inhibin A and B protein complexes. These complexes negatively regulate follicle stimulating hormone secretion from the pituitary gland. Inhibins have also been implicated in regulating numerous cellular processes including cell proliferation, apoptosis, immune response and hormone secretion. Mutations in this gene may be associated with male infertility and premature ovarian failure in female human patients. [provided by RefSeq, Aug 2016]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-219570312-A-GG is Pathogenic according to our data. Variant chr2-219570312-A-GG is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1723324.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
OBSL1	NM_015311.3	c.921delinsCC	p.Tyr308LeufsTer47	frameshift_variant	1/21	ENST00000404537.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
OBSL1	ENST00000404537.6	c.921delinsCC	p.Tyr308LeufsTer47	frameshift_variant	1/21	1	NM_015311.3	P1

Frequencies

GnomAD3 genomes Cov.: 35

GnomAD4 exome Cov.: 64

GnomAD4 genome Cov.: 35

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

3M syndrome 2 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Oct 15, 2022

Variant summary: OBSL1 c.921delinsCC (p.Tyr308LeufsX47) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant was absent in 240848 control chromosomes (gnomAD). To our knowledge, no occurrence of c.921delinsCC in individuals affected with Three M Syndrome 2 and no experimental evidence demonstrating its impact on protein function have been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-220435034;