X-41520424-T-C

Position:

• chrX-41520424-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_001367721.1(CASK):​c.2777A>G​(p.Tyr926Cys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000183 in 1,091,779 control chromosomes in the GnomAD database, with no homozygous occurrence. There are 1 hemizygotes in GnomAD. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 23)
  • Exomes 𝑓: 0.0000018 (0 hom. 1 hem.)
• Consequence: CASK NM_001367721.1 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.67

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-AS1 (HGNC:40126): (CASK antisense RNA 1)

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), CASK. . Gene score misZ 4.2502 (greater than the threshold 3.09). GenCC has associacion of gene with syndromic X-linked intellectual disability Najm type, X-linked syndromic intellectual disability, developmental and epileptic encephalopathy, FG syndrome 4.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.897

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CASK	NM_001367721.1	c.2777A>G	p.Tyr926Cys	missense_variant	27/27	ENST00000378163.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CASK	ENST00000378163.7	c.2777A>G	p.Tyr926Cys	missense_variant	27/27	5	NM_001367721.1	A1
CASK-AS1	ENST00000451126.1	n.331+58T>C		intron_variant, non_coding_transcript_variant		2

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD3 exomes AF: 0.00000554 AC: 1 AN: 180609 Hom.: 0 AF XY: 0.0000153 AC XY: 1 AN XY: 65217

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000124

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000183 AC: 2 AN: 1091779 Hom.: 0 Cov.: 28 AF XY: 0.00000280 AC XY: 1 AN XY: 357681

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000239

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 23

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Intellectual disability, CASK-related, X-linked Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 03, 2019

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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with CASK-related conditions. This variant is present in population databases (rs748918088, ExAC 0.003%). This sequence change replaces tyrosine with cysteine at codon 921 of the CASK protein (p.Tyr921Cys). The tyrosine residue is highly conserved and there is a large physicochemical difference between tyrosine and cysteine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.48	D
BayesDel_noAF	Pathogenic	0.45
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.79	.;.;.;.;.;.;.;D;.;.;.;.;.;.
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D;D;D;D;D;D;D;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.88	D
MetaRNN	Pathogenic	0.90	D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.51	D
MutationAssessor	Uncertain	2.6	.;.;.;.;.;.;.;M;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-7.8	.;.;.;.;.;D;.;D;.;.;.;.;.;.
REVEL	Pathogenic	0.73
Sift	Pathogenic	0.0	.;.;.;.;.;D;.;D;.;.;.;.;.;.
Sift4G	Pathogenic	0.0010	.;.;.;.;.;D;.;D;.;.;.;.;.;.
Polyphen		1.0	D;D;.;D;.;D;.;D;.;.;.;.;.;.
Vest4		0.82
MutPred		0.52		.;.;.;.;.;.;.;Loss of disorder (P = 0.037);.;.;.;.;.;.;
MVP		0.98
MPC		2.5
ClinPred		0.97	D
GERP RS		5.8
Varity_R		0.88
gMVP		0.79

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

Publications

LitVar

Other links and lift over

dbSNP: rs748918088; hg19: chrX-41379677;