14-105855621-CTT-C

Position:

• chr14-105855621-CTT-C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The ENST00000637539.2(IGHM):​c.506_507del​(p.Lys169ArgfsTer84) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000637 in 628,146 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (no stars). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000064 (0 hom.)
• Consequence: IGHM ENST00000637539.2 frameshift
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: -1.21

Genes affected

IGHM (HGNC:5541): (immunoglobulin heavy constant mu) Immunoglobulins (Ig) are the antigen recognition molecules of B cells. An Ig molecule is made up of 2 identical heavy chains and 2 identical light chains (see MIM 147200) joined by disulfide bonds so that each heavy chain is linked to a light chain and the 2 heavy chains are linked together. Each Ig heavy chain has an N-terminal variable (V) region containing the antigen-binding site and a C-terminal constant (C) region, encoded by an individual C region gene, that determines the isotype of the antibody and provides effector or signaling functions. The heavy chain V region is encoded by 1 each of 3 types of genes: V genes (see MIM 147070), joining (J) genes (see MIM 147010), and diversity (D) genes (see MIM 146910). The C region genes are clustered downstream of the V region genes within the heavy chain locus on chromosome 14. The IGHM gene encodes the C region of the mu heavy chain, which defines the IgM isotype. Naive B cells express the transmembrane forms of IgM and IgD (see IGHD; MIM 1471770) on their surface. During an antibody response, activated B cells can switch to the expression of individual downstream heavy chain C region genes by a process of somatic recombination known as isotype switching. In addition, secreted Ig forms that act as antibodies can be produced by alternative RNA processing of the heavy chain C region sequences. Although the membrane forms of all Ig isotypes are monomeric, secreted IgM forms pentamers, and occasionally hexamers, in plasma (summary by Janeway et al., 2005).[supplied by OMIM, Aug 2010]

ACMG classification

Verdict is Pathogenic. Variant got 11 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 14-105855621-CTT-C is Pathogenic according to our data. Variant chr14-105855621-CTT-C is described in ClinVar as [Pathogenic]. Clinvar id is 14812.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
IGHM	ENST00000637539.2	c.506_507del	p.Lys169ArgfsTer84	frameshift_variant	2/6			A2
IGHM	ENST00000390559.6	c.506_507del	p.Lys169ArgfsTer84	frameshift_variant	2/4			P3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000163 AC: 4 AN: 245848 Hom.: 0 AF XY: 0.0000150 AC XY: 2 AN XY: 133606

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000872

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: 0.00000908

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000637 AC: 4 AN: 628146 Hom.: 0 AF XY: 0.00000292 AC XY: 1 AN XY: 342206

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000458

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: 0.00000286

Gnomad4 OTH exome AF: 0.0000303

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Autosomal recessive agammaglobulinemia 1 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Oct 01, 2002

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs782530227; hg19: chr14-106321726;