chr2-108788029-T-TA

Position:

• chr2-108788029-T-TA

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_144978.3(CCDC138):​c.94-2dupA variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000029 in 1,378,202 control chromosomes in the GnomAD database, with no homozygous occurrence. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000029 (0 hom.)
• Consequence: CCDC138 NM_144978.3 splice_acceptor, intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.25

Genes affected

CCDC138 (HGNC:26531): (coiled-coil domain containing 138)

RANBP2 (HGNC:9848): (RAN binding protein 2) RAN is a small GTP-binding protein of the RAS superfamily that is associated with the nuclear membrane and is thought to control a variety of cellular functions through its interactions with other proteins. This gene encodes a very large RAN-binding protein that immunolocalizes to the nuclear pore complex. The protein is a giant scaffold and mosaic cyclophilin-related nucleoporin implicated in the Ran-GTPase cycle. The encoded protein directly interacts with the E2 enzyme UBC9 and strongly enhances SUMO1 transfer from UBC9 to the SUMO1 target SP100. These findings place sumoylation at the cytoplasmic filaments of the nuclear pore complex and suggest that, for some substrates, modification and nuclear import are linked events. This gene is partially duplicated in a gene cluster that lies in a hot spot for recombination on chromosome 2q. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.028528528 fraction of the gene. Cryptic splice site detected, with MaxEntScore 9.2, offset of 0 (no position change), new splice context is: cttttctttttttttttaAGtat. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CCDC138	NM_144978.3	c.94-2dupA		splice_acceptor_variant, intron_variant		ENST00000295124.9	NP_659415.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CCDC138	ENST00000295124.9	c.94-3_94-2insA		splice_acceptor_variant, intron_variant		2	NM_144978.3	ENSP00000295124.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000140 AC: 3 AN: 214564 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 117306

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000400

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000417

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000985

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000290 AC: 4 AN: 1378202 Hom.: 0 Cov.: 26 AF XY: 0.00 AC XY: 0 AN XY: 687980

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000292

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000128

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.44e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.43		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.43		Position offset: 3

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

Publications

LitVar

Other links and lift over

dbSNP: rs35693674; hg19: chr2-109404485;