12-8605439-C-T

Variant names:

• chr12-8605439-C-T
• rs104894325
• NM_020661.4:c.203G>A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_020661.4(AICDA):​c.203G>A​(p.Trp68*) variant causes a stop gained change. The variant allele was found at a frequency of 0.000000684 in 1,461,894 control chromosomes in the GnomAD database, with no homozygous occurrence. 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: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: AICDA NM_020661.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 5.29

Genes affected

AICDA (HGNC:13203): (activation induced cytidine deaminase) This gene encodes a RNA-editing deaminase that is a member of the cytidine deaminase family. AICDA is specifically expressed and active in germinal center-like B cells. In the germinal center, AICDA is involved in somatic hypermutation, gene conversion, and class-switch recombination of immunoglobulin genes. An epigenetic role in neoplastic transformation and lymphoma progression has been experimentally ascribed to AICDA using mouse models. Defects in this gene are the cause of autosomal recessive hyper-IgM immunodeficiency syndrome type 2 (HIGM2). [provided by RefSeq, Jul 2020]

ACMG classification

Verdict is Pathogenic. Variant got 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 12-8605439-C-T is Pathogenic according to our data. Variant chr12-8605439-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 5123.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
AICDA	NM_020661.4	c.203G>A	p.Trp68*	stop_gained	Exon 3 of 5	ENST00000229335.11	NP_065712.1
AICDA	NM_001330343.2	c.203G>A	p.Trp68*	stop_gained	Exon 3 of 5		NP_001317272.1
AICDA	NM_001410970.1	c.203G>A	p.Trp68*	stop_gained	Exon 3 of 4		NP_001397899.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AICDA	ENST00000229335.11	c.203G>A	p.Trp68*	stop_gained	Exon 3 of 5	1	NM_020661.4	ENSP00000229335.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461894 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 727248

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hyper-IgM syndrome type 2 Pathogenic:2

Sep 01, 2000

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Aug 09, 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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. ClinVar contains an entry for this variant (Variation ID: 5123). This premature translational stop signal has been observed in individual(s) with autosomal recessive hyper IgM syndrome (PMID: 11007475, 14962793). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Trp68*) in the AICDA gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in AICDA are known to be pathogenic (PMID: 11007475). -

not provided Pathogenic:1

Jan 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

AICDA: PVS1, PM2 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.63
CADD	Pathogenic	42
DANN	Uncertain	1.0
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Pathogenic	0.99	D
Vest4		0.86
ClinPred		1.0	D
GERP RS		5.4

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs104894325; hg19: chr12-8758035;