14-54847131-C-T
Variant summary
Our verdict is Pathogenic. Variant got 22 ACMG points: 22P and 0B. PVS1PM2PP3_StrongPP5_Very_Strong
The NM_000161.3(GCH1):c.510-1G>A variant causes a splice acceptor change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).
Frequency
Genomes: not found (cov: 32)
Consequence
GCH1
NM_000161.3 splice_acceptor
NM_000161.3 splice_acceptor
Scores
5
1
1
Splicing: ADA: 1.000
2
Clinical Significance
Conservation
PhyloP100: 7.09
Genes affected
GCH1 (HGNC:4193): (GTP cyclohydrolase 1) This gene encodes a member of the GTP cyclohydrolase family. The encoded protein is the first and rate-limiting enzyme in tetrahydrobiopterin (BH4) biosynthesis, catalyzing the conversion of GTP into 7,8-dihydroneopterin triphosphate. BH4 is an essential cofactor required by aromatic amino acid hydroxylases as well as nitric oxide synthases. Mutations in this gene are associated with malignant hyperphenylalaninemia and dopa-responsive dystonia. Several alternatively spliced transcript variants encoding different isoforms have been described; however, not all variants give rise to a functional enzyme. [provided by RefSeq, Jul 2008]
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ACMG classification
Classification made for transcript
Verdict is Pathogenic. Variant got 22 ACMG points.
PVS1
?
Splicing variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 7.2, offset of 1, new splice context is: acaattctttcttttctaAGatt. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
PM2
?
Very rare variant in population databases, with high coverage;
PP3
?
Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
PP5
?
Variant 14-54847131-C-T is Pathogenic according to our data. Variant chr14-54847131-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 447375.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
GCH1 | NM_000161.3 | c.510-1G>A | splice_acceptor_variant | ENST00000491895.7 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
GCH1 | ENST00000491895.7 | c.510-1G>A | splice_acceptor_variant | 1 | NM_000161.3 | P1 |
Frequencies
GnomAD3 genomes ? Cov.: 32
GnomAD3 genomes
?
Cov.:
32
GnomAD4 exome Cov.: 11
GnomAD4 exome
Cov.:
11
GnomAD4 genome ? Cov.: 32
GnomAD4 genome
?
Cov.:
32
ClinVar
Significance: Pathogenic
Submissions summary: Pathogenic:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
not provided Pathogenic:2
Pathogenic, criteria provided, single submitter | clinical testing | GeneDx | Nov 20, 2020 | Canonical splice site variant predicted to result in a null allele in a gene for which loss-of-function is a known mechanism of disease; Not observed in large population cohorts (Lek et al., 2016); Has not been previously published as pathogenic or benign to our knowledge - |
Pathogenic, criteria provided, single submitter | clinical testing | Athena Diagnostics | Dec 22, 2016 | - - |
GTP cyclohydrolase I deficiency;C1851920:Dystonia 5 Pathogenic:1
Pathogenic, criteria provided, single submitter | clinical testing | Invitae | Jul 06, 2023 | This sequence change affects an acceptor splice site in intron 3 of the GCH1 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product. This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individuals with autosomal dominant dystonia and related disorders (PMID: 9566388; Invitae). ClinVar contains an entry for this variant (Variation ID: 447375). Studies have shown that disruption of this splice site results in skipping of exon 4 and introduces a premature termination codon (PMID: 9566388). The resulting mRNA is expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
D
BayesDel_noAF
Pathogenic
Cadd
Pathogenic
Dann
Uncertain
Eigen
Pathogenic
Eigen_PC
Pathogenic
FATHMM_MKL
Pathogenic
D
MutationTaster
Benign
D;D;D;D
GERP RS
Splicing
Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
dbscSNV1_RF
Pathogenic
SpliceAI score (max)
Details are displayed if max score is > 0.2
DS_AG_spliceai
Position offset: -2
DS_AL_spliceai
Position offset: -1
Find out detailed SpliceAI scores and Pangolin per-transcript scores at