17-44913439-G-T

Variant names:

• chr17-44913439-G-T
• rs3744469
• NM_002055.5:c.619-9C>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_002055.5(GFAP):​c.619-9C>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,360 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GFAP NM_002055.5 intron
• Scores: Splicing: ADA: 0.01121
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.42
• Publications: 0 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: ClinGen, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P
• Alexander disease type II

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.8).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GFAP	NM_002055.5	c.619-9C>A		intron_variant	Intron 3 of 8	ENST00000588735.3	NP_002046.1
GFAP	NM_001363846.2	c.619-9C>A		intron_variant	Intron 3 of 9		NP_001350775.1
GFAP	NM_001242376.3	c.619-9C>A		intron_variant	Intron 3 of 6		NP_001229305.1
GFAP	NM_001131019.3	c.619-9C>A		intron_variant	Intron 3 of 7		NP_001124491.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GFAP	ENST00000588735.3	c.619-9C>A		intron_variant	Intron 3 of 8	1	NM_002055.5	ENSP00000466598.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461360 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726976

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33470

American (AMR) AF: 0.00 AC: 0 AN: 44704

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

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

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86214

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53358

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5584

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111850

Other (OTH) AF: 0.00 AC: 0 AN: 60346

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.80
CADD	Benign	8.6
DANN	Benign	0.65
PhyloP100		1.4

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.011
dbscSNV1_RF	Benign	0.098
SpliceAI score (max)		0.010		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: rs3744469; hg19: chr17-42990807;