chr17-44915290-C-T

Variant names:

• chr17-44915290-C-T
• rs797044569
• NM_002055.5:c.197G>A

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP3_Strong PP5

The NM_002055.5(GFAP):​c.197G>A​(p.Arg66Gln) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,798 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R66W) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GFAP NM_002055.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:5 U:1 O:1
• Conservation: PhyloP100: 4.14
• Publications: 6 publications found

Genes affected

GFAP (HGNC:4235): (glial fibrillary acidic protein) This gene encodes one of the major intermediate filament proteins of mature astrocytes. It is used as a marker to distinguish astrocytes from other glial cells during development. Mutations in this gene cause Alexander disease, a rare disorder of astrocytes in the central nervous system. Alternative splicing results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, Oct 2008]

GFAP Gene-Disease associations (from GenCC):

• Alexander disease

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), ClinGen, G2P
• Alexander disease type II

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 11 ACMG points.

• PM1: In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_002055.5
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-44915291-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 1308545.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.963
• PP5: Variant 17-44915290-C-T is Pathogenic according to our data. Variant chr17-44915290-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 190332.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002055.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GFAP	NM_002055.5	MANE Select	c.197G>A	p.Arg66Gln	missense	Exon 1 of 9	NP_002046.1	P14136-1
	GFAP	NM_001363846.2		c.197G>A	p.Arg66Gln	missense	Exon 1 of 10	NP_001350775.1	A0A1X7SBR3
	GFAP	NM_001242376.3		c.197G>A	p.Arg66Gln	missense	Exon 1 of 7	NP_001229305.1	P14136-2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GFAP	ENST00000588735.3	TSL:1 MANE Select	c.197G>A	p.Arg66Gln	missense	Exon 1 of 9	ENSP00000466598.2	P14136-1
	GFAP	ENST00000591327.2	TSL:1	n.210G>A		non_coding_transcript_exon	Exon 1 of 5
	GFAP	ENST00000639277.1	TSL:5	c.197G>A	p.Arg66Gln	missense	Exon 1 of 10	ENSP00000492432.1	A0A1W2PR46

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461798 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727212

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53334

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
2	1	-	Alexander disease (4)
3	-	-	not provided (3)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.47
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	30
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.93	D
Eigen	Uncertain	0.57
Eigen_PC	Uncertain	0.59
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.53	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.8	M
PhyloP100		4.1
PrimateAI	Uncertain	0.68	T
PROVEAN	Uncertain	-3.3	D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.027	D
Polyphen		1.0	D
Vest4		0.69
MutPred		0.83		Loss of MoRF binding (P = 0.0746)
MVP		1.0
MPC		0.58
ClinPred		0.99	D
GERP RS		4.8
PromoterAI		0.0033	Neutral
Varity_R		0.95
gMVP		0.96
Mutation Taster		=6/94	disease causing (ClinVar)

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: rs797044569; hg19: chr17-42992658;