NM_020661.4:c.203G>C

Variant names:

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

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_020661.4(AICDA):​c.203G>C​(p.Trp68Ser) variant causes a missense 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. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: AICDA NM_020661.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 5.29
• Publications: 0 publications found

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]

AICDA Gene-Disease associations (from GenCC):

• hyper-IgM syndrome type 2

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Ambry Genetics, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 13 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 1.3381 (below the threshold of 3.09). Trascript score misZ: 0.98605 (below the threshold of 3.09). GenCC associations: The gene is linked to hyper-IgM syndrome type 2.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_020661.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	AICDA	NM_020661.4	MANE Select	c.203G>C	p.Trp68Ser	missense	Exon 3 of 5	NP_065712.1
	AICDA	NM_001330343.2		c.203G>C	p.Trp68Ser	missense	Exon 3 of 5	NP_001317272.1
	AICDA	NM_001410970.1		c.203G>C	p.Trp68Ser	missense	Exon 3 of 4	NP_001397899.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	AICDA	ENST00000229335.11	TSL:1 MANE Select	c.203G>C	p.Trp68Ser	missense	Exon 3 of 5	ENSP00000229335.6
	AICDA	ENST00000543081.6	TSL:1	c.203G>C	p.Trp68Ser	missense	Exon 3 of 4	ENSP00000439103.2
	AICDA	ENST00000544516.6	TSL:1	c.157-1102G>C		intron	N/A	ENSP00000439538.2

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

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.78
BayesDel_addAF	Uncertain	0.083	D
BayesDel_noAF	Benign	-0.12
CADD	Pathogenic	31
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.46	T
Eigen	Uncertain	0.54
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.86	D
M_CAP	Uncertain	0.11	D
MetaRNN	Uncertain	0.64	D
MetaSVM	Uncertain	-0.16	T
MutationAssessor	Uncertain	2.5	M
PhyloP100		5.3
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-12	D
REVEL	Benign	0.27
Sift	Benign	0.033	D
Sift4G	Benign	0.63	T
Polyphen		0.76	P
Vest4		0.42
MutPred		0.55		Gain of disorder (P = 0.0022)
MVP		0.90
MPC		2.4
ClinPred		1.0	D
GERP RS		5.4
Varity_R		0.96
gMVP		0.87
Mutation Taster		=48/52	disease causing

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: rs104894325; hg19: chr12-8758035;