16-724734-T-A

Variant names:

• chr16-724734-T-A
• rs142136104
• NM_001378030.1:c.712A>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_001378030.1(CCDC78):​c.712A>T​(p.Lys238*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,964 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. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CCDC78 NM_001378030.1 stop_gained
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.0300
• Publications: 0 publications found

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]

CCDC78 Gene-Disease associations (from GenCC):

• congenital myopathy with internal nuclei and atypical cores

  Inheritance: AD Classification: SUPPORTIVE, LIMITED Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae)
• centronuclear myopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 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.712A>T	p.Lys238*	stop_gained	Exon 8 of 14	ENST00000345165.10	NP_001364959.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CCDC78	ENST00000345165.10	c.712A>T	p.Lys238*	stop_gained	Exon 8 of 14	5	NM_001378030.1	ENSP00000316851.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459964 Hom.: 0 Cov.: 38 AF XY: 0.00000138 AC XY: 1 AN XY: 726240

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

African (AFR) AF: 0.00 AC: 0 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44674

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26120

East Asian (EAS) AF: 0.0000252 AC: 1 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86146

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51956

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111808

Other (OTH) AF: 0.00 AC: 0 AN: 60330

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 34

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	35
DANN	Uncertain	0.99
Eigen	Uncertain	0.34
Eigen_PC	Benign	0.028
FATHMM_MKL	Benign	0.34	N
PhyloP100		0.030
Vest4		0.11
ClinPred		0.74	D
GERP RS		3.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.090		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: rs142136104; hg19: chr16-774734;