rs137852815

Variant names:

• chrX-41553843-G-A
• rs137852815
• NM_001367721.1:c.1915C>T

Variant summary

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

The NM_001367721.1(CASK):​c.1915C>T​(p.Arg639*) variant causes a stop gained change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 22)
• Consequence: CASK NM_001367721.1 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 5.72
• Publications: 8 publications found

Genes affected

CASK (HGNC:1497): (calcium/calmodulin dependent serine protein kinase) This gene encodes a calcium/calmodulin-dependent serine protein kinase. The encoded protein is a MAGUK (membrane-associated guanylate kinase) protein family member. These proteins are scaffold proteins and the encoded protein is located at synapses in the brain. Mutations in this gene are associated with FG syndrome 4, intellectual disability and microcephaly with pontine and cerebellar hypoplasia, and a form of X-linked intellectual disability. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2017]

CASK Gene-Disease associations (from GenCC):

• FG syndrome 4

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• syndromic X-linked intellectual disability Najm type

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae)
• X-linked syndromic intellectual disability

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen
• genetic developmental and epileptic encephalopathy

  Inheritance: AD 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 X-41553843-G-A is Pathogenic according to our data. Variant chrX-41553843-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 11530.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
CASK	NM_001367721.1	c.1915C>T	p.Arg639*	stop_gained	Exon 21 of 27	ENST00000378163.7	NP_001354650.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CASK	ENST00000378163.7	c.1915C>T	p.Arg639*	stop_gained	Exon 21 of 27	5	NM_001367721.1	ENSP00000367405.1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 22

Alfa AF: 0.0000258 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Syndromic X-linked intellectual disability Najm type Pathogenic:2

Sep 01, 2008

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

May 04, 2022

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

The hemizygous p.Arg639Ter variant in CASK was identified by our study in 1 individual with mental retardation and microcephaly with pontine and cerebellar hypoplasia. Trio exome analysis showed this variant to be de novo. The variant has been reported in 1 Turkish individual with mental retardation and microcephaly with pontine and cerebellar hypoplasia (PMID: 19165920), but was absent from large population studies. This variant has been reported in ClinVar (Variation ID: 11530) as pathogenic by OMIM and GeneDx. This nonsense variant leads to a premature termination codon at position 639, which is predicted to lead to a truncated or absent protein. Heterozygous loss of function of the CASK gene is an established disease mechanism in mental retardation and microcephaly with pontine and cerebellar hypoplasia. In summary, this variant meets criteria to be classified as pathogenic for mental retardation and microcephaly with pontine and cerebellar hypoplasia in an X-linked dominant manner based on the predicted impact of the variant, and occurrences in affected individuals while absent from control populations. ACMG/AMP Criteria applied: PVS1, PM2, PS4_supporting, PS2 (Richards 2015). -

not provided Pathogenic:1

Jul 22, 2025

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (gnomAD); Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 36703223, 33057194, 35982159, 25525159, 29691940, 19165920, 35670744) -

Intellectual disability Pathogenic:1

Oct 04, 2024

Al Jalila Children’s Genomics Center, Al Jalila Childrens Speciality Hospital

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

PVS1, PS2, PM2 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	39
DANN	Uncertain	1.0
FATHMM_MKL	Benign	0.74	D
PhyloP100		5.7
Vest4		0.96
GERP RS		5.2
Mutation Taster		=0/200	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: rs137852815; hg19: chrX-41413096;