7-100643266-C-G

Variant names:

• chr7-100643266-C-G
• rs377432568
• NM_016188.5:c.1261G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_016188.5(ACTL6B):​c.1261G>C​(p.Val421Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,788 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V421M) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ACTL6B NM_016188.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.83
• Publications: 0 publications found

Genes affected

ACTL6B (HGNC:160): (actin like 6B) The protein encoded by this gene is a member of a family of actin-related proteins (ARPs) which share significant amino acid sequence identity to conventional actins. Both actins and ARPs have an actin fold, which is an ATP-binding cleft, as a common feature. The ARPs are involved in diverse cellular processes, including vesicular transport, spindle orientation, nuclear migration and chromatin remodeling. This gene encodes a subunit of the BAF (BRG1/brm-associated factor) complex in mammals, which is functionally related to SWI/SNF complex in S. cerevisiae and Drosophila; the latter is thought to facilitate transcriptional activation of specific genes by antagonizing chromatin-mediated transcriptional repression. This subunit may be involved in the regulation of genes by structural modulation of their chromatin, specifically in the brain. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Dec 2015]

ACTL6B Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 76

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), G2P
• intellectual developmental disorder with severe speech and ambulation defects

  Inheritance: AD Classification: STRONG, MODERATE, LIMITED Submitted by: G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• syndromic intellectual disability

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• undetermined early-onset epileptic encephalopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the ACTL6B gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 18 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 3.2738 (above the threshold of 3.09). Trascript score misZ: 3.3665 (above the threshold of 3.09). GenCC associations: The gene is linked to intellectual developmental disorder with severe speech and ambulation defects, syndromic intellectual disability, developmental and epileptic encephalopathy, 76, undetermined early-onset epileptic encephalopathy.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.973

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_016188.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACTL6B	NM_016188.5	MANE Select	c.1261G>C	p.Val421Leu	missense	Exon 14 of 14	NP_057272.1	O94805
	ACTL6B	NR_134539.2		n.1372G>C		non_coding_transcript_exon	Exon 14 of 14

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	ACTL6B	ENST00000160382.10	TSL:1 MANE Select	c.1261G>C	p.Val421Leu	missense	Exon 14 of 14	ENSP00000160382.5	O94805
	ACTL6B	ENST00000970942.1		c.1330G>C	p.Val444Leu	missense	Exon 15 of 15	ENSP00000641001.1
	ACTL6B	ENST00000970941.1		c.1174G>C	p.Val392Leu	missense	Exon 13 of 13	ENSP00000641000.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461788 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727198

⚠️ 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: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53376

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5756

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111974

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ 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.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.93
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.040
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.53
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.52	D
MetaRNN	Pathogenic	0.97	D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Benign	1.9	L
PhyloP100		7.8
PrimateAI	Pathogenic	0.80	D
PROVEAN	Uncertain	-2.4	N
REVEL	Pathogenic	0.83
Sift	Benign	0.082	T
Sift4G	Uncertain	0.044	D
Polyphen		1.0	D
Vest4		0.84
MutPred		0.84		Gain of catalytic residue at V421 (P = 0.0062)
MVP		0.78
MPC		1.6
ClinPred		0.96	D
GERP RS		3.8
Varity_R		0.22
gMVP		0.43
Mutation Taster		=68/32	polymorphism

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

Other links and lift over

dbSNP: rs377432568; hg19: chr7-100240889;