chr2-97724052-G-A

Variant names:

• chr2-97724052-G-A
• rs1677267957
• NM_001079.4:c.16G>A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_001079.4(ZAP70):​c.16G>A​(p.Ala6Thr) variant causes a missense change. The variant allele was found at a frequency of 0.00000214 in 1,401,386 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: ZAP70 NM_001079.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.34

Genes affected

ZAP70 (HGNC:12858): (zeta chain of T cell receptor associated protein kinase 70) This gene encodes an enzyme belonging to the protein tyrosine kinase family, and it plays a role in T-cell development and lymphocyte activation. This enzyme, which is phosphorylated on tyrosine residues upon T-cell antigen receptor (TCR) stimulation, functions in the initial step of TCR-mediated signal transduction in combination with the Src family kinases, Lck and Fyn. This enzyme is also essential for thymocyte development. Mutations in this gene cause selective T-cell defect, a severe combined immunodeficiency disease characterized by a selective absence of CD8-positive T-cells. Two transcript variants that encode different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.27055597).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
ZAP70	NM_001079.4	c.16G>A	p.Ala6Thr	missense_variant	Exon 3 of 14	ENST00000264972.10	NP_001070.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
ZAP70	ENST00000264972.10	c.16G>A	p.Ala6Thr	missense_variant	Exon 3 of 14	1	NM_001079.4	ENSP00000264972.5
ZAP70	ENST00000698508.1	c.16G>A	p.Ala6Thr	missense_variant	Exon 2 of 13			ENSP00000513759.1
ZAP70	ENST00000483781.5	n.209G>A		non_coding_transcript_exon_variant	Exon 3 of 7	2
ZAP70	ENST00000698509.1	n.156G>A		non_coding_transcript_exon_variant	Exon 1 of 12

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000214 AC: 3 AN: 1401386 Hom.: 0 Cov.: 32 AF XY: 0.00000288 AC XY: 2 AN XY: 693524

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000815

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.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

ZAP70-Related Severe Combined Immunodeficiency Uncertain:1

Aug 18, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine with threonine at codon 6 of the ZAP70 protein (p.Ala6Thr). The alanine residue is moderately conserved and there is a small physicochemical difference between alanine and threonine. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This variant has not been reported in the literature in individuals with ZAP70-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.093
BayesDel_addAF	Benign	-0.023	T
BayesDel_noAF	Benign	-0.27
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.35	T
Eigen	Benign	0.058
Eigen_PC	Benign	0.21
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Benign	0.82	T
M_CAP	Benign	0.026	D
MetaRNN	Benign	0.27	T
MetaSVM	Benign	-0.75	T
MutationAssessor	Benign	0.84	L
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-0.55	N
REVEL	Benign	0.078
Sift	Benign	0.56	T
Sift4G	Benign	0.58	T
Polyphen		0.47	P
Vest4		0.42
MutPred		0.21		Gain of glycosylation at A6 (P = 0.0107);
MVP		0.76
MPC		0.74
ClinPred		0.63	D
GERP RS		5.0
Varity_R		0.34
gMVP		0.25

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1677267957; hg19: chr2-98340515;