chr12-8605268-C-G

Variant names:

• chr12-8605268-C-G
• rs193922704
• NM_020661.4:c.374G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM2 PM5 PP2 PP3_Moderate

The NM_020661.4(AICDA):​c.374G>C​(p.Gly125Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G125E) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: AICDA NM_020661.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.34
• 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: Likely_pathogenic. The variant received 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr12-8605268-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 35656.
• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.917

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AICDA	NM_020661.4	c.374G>C	p.Gly125Ala	missense_variant	Exon 3 of 5	ENST00000229335.11	NP_065712.1
AICDA	NM_001330343.2	c.374G>C	p.Gly125Ala	missense_variant	Exon 3 of 5		NP_001317272.1
AICDA	NM_001410970.1	c.374G>C	p.Gly125Ala	missense_variant	Exon 3 of 4		NP_001397899.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AICDA	ENST00000229335.11	c.374G>C	p.Gly125Ala	missense_variant	Exon 3 of 5	1	NM_020661.4	ENSP00000229335.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.70
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.26
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.41	T;.
Eigen	Uncertain	0.36
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.88	D;D
M_CAP	Uncertain	0.12	D
MetaRNN	Pathogenic	0.92	D;D
MetaSVM	Uncertain	0.17	D
MutationAssessor	Benign	1.8	L;L
PhyloP100		7.3
PrimateAI	Uncertain	0.75	T
PROVEAN	Pathogenic	-4.9	D;D
REVEL	Pathogenic	0.78
Sift	Benign	0.12	T;T
Sift4G	Benign	0.12	T;T
Polyphen		1.0	D;.
Vest4		0.91
MutPred		0.79		Loss of ubiquitination at K120 (P = 0.0877);Loss of ubiquitination at K120 (P = 0.0877);
MVP		0.88
MPC		2.0
ClinPred		0.99	D
GERP RS		5.3
Varity_R		0.91
gMVP		0.90
Mutation Taster		=12/88	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: rs193922704; hg19: chr12-8757864;