chr4-3485601-AT-A

Variant names:

• chr4-3485601-AT-A
• rs797045528
• NM_173660.5:c.596delT

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_173660.5(DOK7):​c.596delT​(p.Ile199ThrfsTer47) variant causes a frameshift change. The variant allele was found at a frequency of 0.00000344 in 1,455,508 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. I199I) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 34)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: DOK7 NM_173660.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 4.60
• Publications: 2 publications found

Genes affected

DOK7 (HGNC:26594): (docking protein 7) The protein encoded by this gene is essential for neuromuscular synaptogenesis. The protein functions in aneural activation of muscle-specific receptor kinase, which is required for postsynaptic differentiation, and in the subsequent clustering of the acetylcholine receptor in myotubes. This protein can also induce autophosphorylation of muscle-specific receptor kinase. Mutations in this gene are a cause of familial limb-girdle myasthenia autosomal recessive, which is also known as congenital myasthenic syndrome type 1B. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2009]

DOK7 Gene-Disease associations (from GenCC):

• congenital myasthenic syndrome 10

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), PanelApp Australia
• fetal akinesia deformation sequence 3

  Inheritance: AR Classification: STRONG, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• fetal akinesia deformation sequence 1

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• postsynaptic congenital myasthenic syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-3485601-AT-A is Pathogenic according to our data. Variant chr4-3485601-AT-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 210856.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DOK7	NM_173660.5	c.596delT	p.Ile199ThrfsTer47	frameshift_variant	Exon 5 of 7	ENST00000340083.6	NP_775931.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DOK7	ENST00000340083.6	c.596delT	p.Ile199ThrfsTer47	frameshift_variant	Exon 5 of 7	1	NM_173660.5	ENSP00000344432.5

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD2 exomes AF: 0.0000122 AC: 3 AN: 245722 AF XY: 0.00000750

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000270

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000344 AC: 5 AN: 1455508 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 723988

African (AFR) AF: 0.00 AC: 0 AN: 33248

American (AMR) AF: 0.00 AC: 0 AN: 44328

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26004

East Asian (EAS) AF: 0.00 AC: 0 AN: 39196

South Asian (SAS) AF: 0.00 AC: 0 AN: 85416

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52550

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5754

European-Non Finnish (NFE) AF: 0.00000451 AC: 5 AN: 1108880

Other (OTH) AF: 0.00 AC: 0 AN: 60132

GnomAD4 genome Cov.: 34

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital myasthenic syndrome 10 Pathogenic:1

Jun 02, 2015

Genetic Services Laboratory, University of Chicago

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Fetal akinesia deformation sequence 1;C1850792:Congenital myasthenic syndrome 10 Pathogenic:1

Oct 09, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ile199Thrfs*47) in the DOK7 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 306 amino acid(s) of the DOK7 protein. This variant is present in population databases (rs797045528, gnomAD 0.002%). This premature translational stop signal has been observed in individual(s) with congenital myasthenic syndrome (PMID: 18626973). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 210856). Studies have shown that this premature translational stop signal alters DOK7 gene expression (PMID: 18626973). This variant disrupts a region of the DOK7 protein in which other variant(s) (p.Asp433Argfs*18) have been determined to be pathogenic (PMID: 17439981, 22661499; internal data). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Fetal akinesia deformation sequence 3 Pathogenic:1

Mar 13, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Jan 17, 2023

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); Frameshift variant predicted to result in protein truncation, as the last 306 amino acids are replaced with 46 different amino acids, and other loss-of-function variants have been reported downstream in HGMD.; This variant is associated with the following publications: (PMID: 18626973) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		4.6
Mutation Taster		=2/198	disease causing (ClinVar)

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: rs797045528; hg19: chr4-3487328;