NM_000061.3:c.1926delC

Variant names:

• chrX-101349938-TG-T
• NM_000061.3:c.1926delC

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_000061.3(BTK):​c.1926delC​(p.Thr643LeufsTer6) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 22)
• Consequence: BTK NM_000061.3 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: -0.104
• Publications: 0 publications found

Genes affected

BTK (HGNC:1133): (Bruton tyrosine kinase) The protein encoded by this gene plays a crucial role in B-cell development. Mutations in this gene cause X-linked agammaglobulinemia type 1, which is an immunodeficiency characterized by the failure to produce mature B lymphocytes, and associated with a failure of Ig heavy chain rearrangement. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Dec 2013]

BTK Gene-Disease associations (from GenCC):

• Bruton-type agammaglobulinemia

  Inheritance: XL Classification: DEFINITIVE, SUPPORTIVE Submitted by: Myriad Women’s Health, Orphanet, ClinGen
• isolated growth hormone deficiency type III

  Inheritance: XL Classification: STRONG, NO_KNOWN Submitted by: ClinGen, Labcorp Genetics (formerly Invitae)
• short stature due to isolated growth hormone deficiency with X-linked hypogammaglobulinemia

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 7 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-101349938-TG-T is Pathogenic according to our data. Variant chrX-101349938-TG-T is described in ClinVar as [Pathogenic]. Clinvar id is 2022872.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
BTK	NM_000061.3	c.1926delC	p.Thr643LeufsTer6	frameshift_variant	Exon 19 of 19	ENST00000308731.8	NP_000052.1
BTK	NM_001287344.2	c.2028delC	p.Thr677LeufsTer6	frameshift_variant	Exon 19 of 19		NP_001274273.1
BTK	NM_001287345.2	c.1398delC	p.Thr467LeufsTer6	frameshift_variant	Exon 17 of 17		NP_001274274.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
BTK	ENST00000308731.8	c.1926delC	p.Thr643LeufsTer6	frameshift_variant	Exon 19 of 19	1	NM_000061.3	ENSP00000308176.8

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 22

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

X-linked agammaglobulinemia with growth hormone deficiency Pathogenic:1

Oct 26, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. This sequence change creates a premature translational stop signal (p.Thr643Leufs*6) in the BTK gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 17 amino acid(s) of the BTK protein. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with BTK-related conditions. This variant disrupts a region of the BTK protein in which other variant(s) (p.Phe644Ser) have been determined to be pathogenic (PMID: 8695804, 32552675). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		-0.10

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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

hg19: chrX-100604926;