13-36819377-C-T

Variant summary

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

The NM_000538.4(RFXAP):c.20C>T(p.Ala7Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000876 in 1,141,646 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 8.8e-7 (0 hom.)
• Consequence: RFXAP NM_000538.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.210

Genes affected

RFXAP (HGNC:9988): (regulatory factor X associated 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 ankyrin-containing 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. Mutations in this gene have been linked to bare lymphocyte syndrome type II, complementation group D. Transcript variants utilizing different polyA signals have been found for this gene. [provided by RefSeq, Jul 2008]

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=0.04910308).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
RFXAP	NM_000538.4	c.20C>T	p.Ala7Val	missense_variant	1/3	ENST00000255476.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
RFXAP	ENST00000255476.3	c.20C>T	p.Ala7Val	missense_variant	1/3	1	NM_000538.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 8.76e-7 AC: 1 AN: 1141646 Hom.: 0 Cov.: 31 AF XY: 0.00000183 AC XY: 1 AN XY: 545904

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: 0.00000104

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

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

Invitae

Jan 17, 2022

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. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The valine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. This variant has not been reported in the literature in individuals affected with RFXAP-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 7 of the RFXAP protein (p.Ala7Val). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.21	T
BayesDel_noAF	Benign	-0.54
Cadd	Benign	10
Dann	Uncertain	0.99
DEOGEN2	Benign	0.032	T
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.13	N
LIST_S2	Benign	0.42	T
M_CAP	Benign	0.051	D
MetaRNN	Benign	0.049	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.0	N
MutationTaster	Benign	1.0	N
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	-0.48	N
REVEL	Benign	0.0080
Sift	Benign	0.13	T
Sift4G	Benign	1.0	T
Polyphen		0.0030	B
Vest4		0.095
MutPred		0.21		Gain of catalytic residue at V6 (P = 0.0032);
MVP		0.12
MPC		1.0
ClinPred		0.077	T
GERP RS		-0.55
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.036
gMVP		0.087

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: rs1042508480; hg19: chr13-37393514;