16-722790-C-CG

Variant names:

• chr16-722790-C-CG
• rs1364277352
• NM_001378030.1:c.1302-2_1302-1insC

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_001378030.1(CCDC78):​c.1302-2_1302-1insC variant causes a splice acceptor, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,200 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 34)
• Consequence: CCDC78 NM_001378030.1 splice_acceptor, intron
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.433

Genes affected

CCDC78 (HGNC:14153): (coiled-coil domain containing 78) Involved in de novo centriole assembly involved in multi-ciliated epithelial cell differentiation and skeletal muscle contraction. Located in several cellular components, including centriole; deuterosome; and sarcolemma. Implicated in centronuclear myopathy 4. [provided by Alliance of Genome Resources, Apr 2022]

ANTKMT (HGNC:14152): (adenine nucleotide translocase lysine methyltransferase) Enables protein-lysine N-methyltransferase activity. Involved in peptidyl-lysine trimethylation. Located in mitochondrion. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CCDC78	NM_001378030.1	c.1302-2_1302-1insC		splice_acceptor_variant, intron_variant	Intron 13 of 13	ENST00000345165.10	NP_001364959.1
ANTKMT	NM_023933.3	c.*233_*234insG		downstream_gene_variant		ENST00000569529.6	NP_076422.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CCDC78	ENST00000345165.10	c.1302-2_1302-1insC		splice_acceptor_variant, intron_variant	Intron 13 of 13	5	NM_001378030.1	ENSP00000316851.5
ANTKMT	ENST00000569529.6	c.*233_*234insG		downstream_gene_variant		1	NM_023933.3	ENSP00000454380.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152200 Hom.: 0 Cov.: 34

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 34

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152200 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 74356

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital myopathy with internal nuclei and atypical cores Uncertain:1

Dec 31, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 13 of the CCDC78 gene. It does not directly change the encoded amino acid sequence of the CCDC78 protein. It affects a nucleotide within the consensus splice site. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CCDC78-related conditions. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.92		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.25		Position offset: 35
DS_AL_spliceai		0.92		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1364277352; hg19: chr16-772790;