rs369661042

Variant names:

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_ModerateBP6BS1

The NM_000161.3(GCH1):c.509+3A>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000615 in 1,560,970 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000060 ( 0 hom. )

Consequence

GCH1
NM_000161.3 splice_region, intron

Scores

Splicing: ADA: 0.0009482

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:2

Conservation

PhyloP100: 0.685

Publications

0 publications found

Variant links:

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]

GCH1 Gene-Disease associations (from GenCC):

dystonia 5
Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Orphanet, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), G2P
GTP cyclohydrolase I deficiency with hyperphenylalaninemia
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet, G2P
GTP cyclohydrolase I deficiency
Inheritance: SD, AD Classification: DEFINITIVE Submitted by: ClinGen, Illumina

GCH1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -7 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.41).

BP6

Variant 14-54859678-T-C is Benign according to our data. Variant chr14-54859678-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 459900.

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.0000723 (11/152192) while in subpopulation NFE AF = 0.000147 (10/68040). AF 95% confidence interval is 0.0000791. There are 0 homozygotes in GnomAd4. There are 6 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GCH1	NM_000161.3 link	c.509+3A>G		splice_region_variant, intron_variant	Intron 3 of 5	ENST00000491895.7	NP_000152.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GCH1	ENST00000491895.7 link	c.509+3A>G		splice_region_variant, intron_variant	Intron 3 of 5	1	NM_000161.3	ENSP00000419045.2

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.0000941

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000955

AC:

AN:

251256

AF XY:

0.000118

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000185

Gnomad NFE exome

AF:

0.000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000603

AC:

AN:

1408778

Hom.:

Cov.:

AF XY:

0.0000653

AC XY:

AN XY:

704238

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

32370

American (AMR)

AF:

0.00

AC:

AN:

44646

Ashkenazi Jewish (ASJ)

AF:

0.0000388

AC:

AN:

25798

East Asian (EAS)

AF:

0.00

AC:

AN:

39432

South Asian (SAS)

AF:

0.00

AC:

AN:

85168

European-Finnish (FIN)

AF:

0.000262

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5678

European-Non Finnish (NFE)

AF:

0.0000639

AC:

AN:

1063752

Other (OTH)

AF:

0.0000342

AC:

AN:

58534

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.471

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000723

AC:

AN:

152192

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74356

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41432

American (AMR)

AF:

0.00

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5202

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.0000941

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000147

AC:

AN:

68040

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000103

Hom.:

Bravo

AF:

0.0000604

EpiCase

AF:

0.000327

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1Benign:1

Feb 16, 2025

Laboratory of Genetics, Children's Clinical University Hospital Latvia

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Dec 10, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: GCH1 c.509+3A>G alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Consensus agreement among computation tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 9.6e-05 in 251256 control chromosomes (gnomAD). This frequency is not significantly higher than estimated for a pathogenic variant in GCH1 causing Dystonia 5, allowing no conclusion about variant significance. c.509+3A>G has been reported in the literature in an individual affected with Dystonia without strong evidence of causality (Zirn_2008). This report does not provide unequivocal conclusions about association of the variant with Dystonia 5. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 17898029). ClinVar contains an entry for this variant (Variation ID: 459900). Based on the evidence outlined above, the variant was classified as uncertain significance.

GTP cyclohydrolase I deficiency

Uncertain:1

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.

GTP cyclohydrolase I deficiency;C1851920:Dystonia 5

Uncertain:1

Oct 03, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change falls in intron 3 of the GCH1 gene. It does not directly change the encoded amino acid sequence of the GCH1 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs369661042, gnomAD 0.02%). This variant has been observed in individual(s) with dystonia (PMID: 17898029). ClinVar contains an entry for this variant (Variation ID: 459900). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. 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.

not provided

Uncertain:1

Jul 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

GCH1: PM2

Dystonia 5

Uncertain:1

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance.

Intellectual disability

Benign:1

Sep 11, 2019

Cambridge Genomics Laboratory, East Genomic Laboratory Hub, NHS Genomic Medicine Service

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.41

CADD

Benign

(source)

DANN

Benign

0.81

PhyloP100

0.69

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

2.8

Mutation Taster

=4/96

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00095

dbscSNV1_RF

Benign

0.070

SpliceAI score (max)

0.33

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.33

Position offset: 3

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over