chr19-19193993-C-A

Position:

• chr19-19193993-C-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_003721.4(RFXANK):​c.47C>A​(p.Thr16Asn) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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 benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T16I) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: RFXANK NM_003721.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.829

Genes affected

RFXANK (HGNC:9987): (regulatory factor X associated ankyrin containing protein) Major histocompatibility (MHC) class II molecules are transmembrane proteins that have a central role in development and control of the immune system. The protein encoded by this gene, along with regulatory factor X-associated protein and regulatory factor-5, forms a complex that binds to the X box motif of certain MHC class II gene promoters and activates their transcription. Once bound to the promoter, this complex associates with the non-DNA-binding factor MHC class II transactivator, which controls the cell type specificity and inducibility of MHC class II gene expression. This protein contains ankyrin repeats involved in protein-protein interactions. Mutations in this gene have been linked to bare lymphocyte syndrome type II, complementation group B. Multiple alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq, Jul 2013]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.062065452).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RFXANK	NM_003721.4	c.47C>A	p.Thr16Asn	missense_variant	3/10	ENST00000303088.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RFXANK	ENST00000303088.9	c.47C>A	p.Thr16Asn	missense_variant	3/10	1	NM_003721.4	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461894 Hom.: 0 Cov.: 32 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.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

MHC class II deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 01, 2021

This sequence change replaces threonine with asparagine at codon 16 of the RFXANK protein (p.Thr16Asn). The threonine residue is weakly conserved and there is a small physicochemical difference between threonine and asparagine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals affected with RFXANK-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. 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	0.065
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.53
CADD	Benign	16
DANN	Benign	0.85
DEOGEN2	Benign	0.030	T;T;.;.;T;.;T
Eigen	Benign	-1.0
Eigen_PC	Benign	-1.0
FATHMM_MKL	Benign	0.11	N
LIST_S2	Benign	0.54	T;.;T;T;T;T;T
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.062	T;T;T;T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.0	.;N;N;.;N;.;.
MutationTaster	Benign	1.0	N;N;N;N;N
PrimateAI	Benign	0.33	T
PROVEAN	Benign	-1.3	N;N;N;.;N;N;N
REVEL	Benign	0.026
Sift	Benign	0.053	T;T;T;.;T;T;T
Sift4G	Benign	0.23	T;T;T;T;T;T;T
Polyphen		0.013	.;B;.;.;B;.;.
Vest4		0.11, 0.16, 0.11, 0.17
MutPred		0.15		Loss of phosphorylation at T16 (P = 0.0344);Loss of phosphorylation at T16 (P = 0.0344);Loss of phosphorylation at T16 (P = 0.0344);Loss of phosphorylation at T16 (P = 0.0344);Loss of phosphorylation at T16 (P = 0.0344);Loss of phosphorylation at T16 (P = 0.0344);Loss of phosphorylation at T16 (P = 0.0344);
MVP		0.76
MPC		0.29
ClinPred		0.029	T
GERP RS		2.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.041
gMVP		0.25

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: rs764499202; hg19: chr19-19304802;