NM_002025.4:c.148C>A

Variant names:

• chrX-148652099-C-A
• rs2054208339
• NM_002025.4:c.148C>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_002025.4(AFF2):​c.148C>A​(p.Leu50Ile) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 23)
• Consequence: AFF2 NM_002025.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.88
• Publications: 0 publications found

Genes affected

AFF2 (HGNC:3776): (ALF transcription elongation factor 2) This gene encodes a putative transcriptional activator that is a member of the AF4\FMR2 gene family. This gene is associated with the folate-sensitive fragile X E locus on chromosome X. A repeat polymorphism in the fragile X E locus results in silencing of this gene causing Fragile X E syndrome. Fragile X E syndrome is a form of nonsyndromic X-linked cognitive disability. In addition, this gene contains 6-25 GCC repeats that are expanded to >200 repeats in the disease state. Alternate splicing results in multiple transcript variants.[provided by RefSeq, Jul 2016]

AFF2 Gene-Disease associations (from GenCC):

• FRAXE intellectual disability

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae)
• non-syndromic X-linked intellectual disability

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.912

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
AFF2	NM_002025.4	c.148C>A	p.Leu50Ile	missense_variant	Exon 2 of 21	ENST00000370460.7	NP_002016.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
AFF2	ENST00000370460.7	c.148C>A	p.Leu50Ile	missense_variant	Exon 2 of 21	5	NM_002025.4	ENSP00000359489.2
AFF2	ENST00000342251.7	c.148C>A	p.Leu50Ile	missense_variant	Exon 2 of 20	1		ENSP00000345459.4
AFF2	ENST00000370457.9	c.148C>A	p.Leu50Ile	missense_variant	Exon 2 of 20	1		ENSP00000359486.6
AFF2	ENST00000370458.5	c.148C>A	p.Leu50Ile	missense_variant	Exon 2 of 8	1		ENSP00000359487.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 26

GnomAD4 genome Cov.: 23

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jul 03, 2020

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.54
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.53	D;.;.;.
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.92	D;D;D;D
M_CAP	Pathogenic	0.81	D
MetaRNN	Pathogenic	0.91	D;D;D;D
MetaSVM	Uncertain	0.18	D
MutationAssessor	Pathogenic	3.1	M;M;M;M
PhyloP100		5.9
PrimateAI	Uncertain	0.72	T
PROVEAN	Benign	-1.5	N;N;N;N
REVEL	Uncertain	0.61
Sift	Pathogenic	0.0	D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D
Polyphen		1.0	D;D;D;D
Vest4		0.61
MutPred		0.81		Loss of disorder (P = 0.1063);Loss of disorder (P = 0.1063);Loss of disorder (P = 0.1063);Loss of disorder (P = 0.1063);
MVP		0.87
MPC		0.63
ClinPred		0.99	D
GERP RS		5.6
Varity_R		0.70
gMVP		0.60
Mutation Taster		=28/72	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: rs2054208339; hg19: chrX-147733620;