rs1555844395

chr20-44624205-G-Cchr20-44624205-G-T

Variant summary

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

The NM_000022.4(ADA):c.603C>G(p.Tyr201Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,458,990 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 (★★★). Synonymous variant affecting the same amino acid position (i.e. Y201Y) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: ADA NM_000022.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:2
• Conservation: PhyloP100: -0.911

Genes affected

ADA (HGNC:186): (adenosine deaminase) This gene encodes an enzyme that catalyzes the hydrolysis of adenosine to inosine in the purine catabolic pathway. Various mutations have been described for this gene and have been linked to human diseases related to impaired immune function such as severe combined immunodeficiency disease (SCID) which is the result of a deficiency in the ADA enzyme. In ADA-deficient individuals there is a marked depletion of T, B, and NK lymphocytes, and consequently, a lack of both humoral and cellular immunity. Conversely, elevated levels of this enzyme are associated with congenital hemolytic anemia. [provided by RefSeq, Sep 2019]

PKIG (HGNC:9019): (cAMP-dependent protein kinase inhibitor gamma) This gene encodes a member of the protein kinase inhibitor family. Studies of a similar protein in mice suggest that this protein acts as a potent competitive cAMP-dependent protein kinase inhibitor, and is a predominant form of inhibitor in various tissues. The encoded protein may be involved in osteogenesis. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2013]

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 20-44624205-G-C is Pathogenic according to our data. Variant chr20-44624205-G-C is described in ClinVar as [Pathogenic]. Clinvar id is 555182.Status of the report is reviewed_by_expert_panel, 3 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ADA	NM_000022.4	c.603C>G	p.Tyr201Ter	stop_gained	6/12	ENST00000372874.9
ADA	NM_001322051.2	c.603C>G	p.Tyr201Ter	stop_gained	6/11
ADA	NM_001322050.2	c.198C>G	p.Tyr66Ter	stop_gained	5/11
ADA	NR_136160.2	n.695C>G		non_coding_transcript_exon_variant	6/11

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ADA	ENST00000372874.9	c.603C>G	p.Tyr201Ter	stop_gained	6/12	1	NM_000022.4	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1458990 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 725600

Gnomad4 AFR exome AF: 0.0000299

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: reviewed by expert panel

Submissions by phenotype

Severe combined immunodeficiency, autosomal recessive, T cell-negative, B cell-negative, NK cell-negative, due to adenosine deaminase deficiency Pathogenic:2

Pathogenic, reviewed by expert panel	curation	ClinGen Severe Combined Immunodeficiency Variant Curation Expert Panel, ClinGen	Jan 24, 2024	The c.603C>G (p.Tyr201Ter) (NM_000022.4) variant in ADA is a nonsense variant predicted to cause a premature stop codon in biologically-relevant-exon 6/12 leading to nonsense-mediated decay in a gene in which loss-of-function is an established disease mechanism (PVS1_Met). The highest population minor allele frequency in gnomAD v4 is 0.00002992 (1/33422 alleles) in African/African American population, which is lower than the ClinGen SCID VCEP threshold (<0.0001742) for PM2_Supporting, and therefore meets this criterion (PM2_Supporting). There are no publications for this variant in the literature. Patient # 46 was found to be heterozygous for c.603C>G (p.Tyr201*) and c.632G>A (p.Arg211His) which is classified as pathogenic for SCID by the ClinGen SCID VCEP (1 pt.) (PMID: 26255240, PM3). In summary, this variant meets the criteria to be classified as a Pathogenic variant for autosomal recessive severe combined immunodeficiency due to ADA deficiency based on the ACMG/AMP criteria applied, as specified by the ClinGen SCID VCEP: PM2_supporting,PM3,PVS1 (VCEP specifications version 1). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Nov 21, 2017	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.020
Cadd	Uncertain	24
Dann	Benign	0.94
Eigen	Benign	-0.51
Eigen_PC	Benign	-0.95
FATHMM_MKL	Benign	0.35	N
MutationTaster	Benign	1.0	A;A;D
Vest4		0.92
GERP RS		-9.7

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555844395; hg19: chr20-43252846;