chr22-24302301-G-GA

Position:

• chr22-24302301-G-GA

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The NM_015330.6(SPECC1L):​c.76dupA​(p.Ile26fs) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000684 in 1,461,880 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SPECC1L NM_015330.6 frameshift
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.09

Genes affected

SPECC1L (HGNC:29022): (sperm antigen with calponin homology and coiled-coil domains 1 like) This gene encodes a coiled-coil domain containing protein. The encoded protein may play a critical role in actin-cytoskeletal reorganization during facial morphogenesis. Mutations in this gene are a cause of oblique facial clefting-1. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. A read-through transcript composed of SPECC1L (sperm antigen with calponin homology and coiled-coil domains 1-like) and the downstream ADORA2A (adenosine A2a receptor) gene sequence has been identified, but it is thought to be non-coding. [provided by RefSeq, Jun 2013]

SPECC1L-ADORA2A (HGNC:49185): (SPECC1L-ADORA2A readthrough (NMD candidate)) This locus represents naturally occurring readthrough transcription between the neighboring SPECC1L (sperm antigen with calponin homology and coiled-coil domains 1-like) and ADORA2A (adenosine A2a receptor) genes on chromosome 22. The readthrough transcript is a candidate for nonsense-mediated mRNA decay (NMD) and is unlikely to produce a protein product. [provided by RefSeq, Jun 2013]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 6 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SPECC1L	NM_015330.6	c.76dupA	p.Ile26fs	frameshift_variant	3/17	ENST00000314328.14	NP_056145.5
SPECC1L	NM_001145468.4	c.76dupA	p.Ile26fs	frameshift_variant	2/16		NP_001138940.4
SPECC1L	NM_001254732.3	c.76dupA	p.Ile26fs	frameshift_variant	2/15		NP_001241661.3
SPECC1L-ADORA2A	NR_103546.1	n.384dupA		non_coding_transcript_exon_variant	3/20

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SPECC1L	ENST00000314328.14	c.76dupA	p.Ile26fs	frameshift_variant	3/17	1	NM_015330.6	ENSP00000325785.8
SPECC1L-ADORA2A	ENST00000358654.2	n.76dupA		non_coding_transcript_exon_variant	3/20	2		ENSP00000351480.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461880 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727240

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jan 21, 2024

Not observed at significant frequency in large population cohorts (gnomAD); Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene or region of a gene for which loss of function is not a well-established mechanism of disease; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr22-24698269;