rs137852633

Variant names:

• chr14-54845799-G-C
• rs137852633
• NM_000161.3:c.595C>G

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PM1 PM2 PP2 PP3_Strong PP5

The NM_000161.3(GCH1):​c.595C>G​(p.Pro199Ala) variant causes a missense change involving the alteration of a conserved nucleotide. 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 Pathogenic (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P199L) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: GCH1 NM_000161.3 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 10.0
• Publications: 3 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000161.3
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 30 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 1.5191 (below the threshold of 3.09). Trascript score misZ: 0.62455 (below the threshold of 3.09). GenCC associations: The gene is linked to GTP cyclohydrolase I deficiency, dystonia 5, GTP cyclohydrolase I deficiency with hyperphenylalaninemia.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 14-54845799-G-C is Pathogenic according to our data. Variant chr14-54845799-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 9292.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GCH1	NM_000161.3	c.595C>G	p.Pro199Ala	missense_variant	Exon 5 of 6	ENST00000491895.7	NP_000152.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GCH1	ENST00000491895.7	c.595C>G	p.Pro199Ala	missense_variant	Exon 5 of 6	1	NM_000161.3	ENSP00000419045.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Dystonia, dopa-responsive, with or without hyperphenylalaninemia, autosomal recessive Pathogenic:1

Jan 01, 2004

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.88
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.49
CADD	Pathogenic	28
DANN	Uncertain	0.98
DEOGEN2	Pathogenic	0.92	D;D;.;D;.
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.99	.;D;D;.;D
M_CAP	Pathogenic	0.51	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.4	M;M;M;M;M
PhyloP100		10
PrimateAI	Uncertain	0.61	T
PROVEAN	Pathogenic	-7.6	.;D;D;D;D
REVEL	Pathogenic	0.73
Sift	Benign	0.11	.;T;T;T;T
Sift4G	Benign	0.092	T;T;T;T;D
Polyphen		1.0	D;D;D;D;D
Vest4		0.91
MutPred		0.94		Gain of MoRF binding (P = 0.054);Gain of MoRF binding (P = 0.054);Gain of MoRF binding (P = 0.054);Gain of MoRF binding (P = 0.054);Gain of MoRF binding (P = 0.054);
MVP		0.94
MPC		2.2
ClinPred		0.99	D
GERP RS		6.2
Varity_R		0.87
gMVP		0.97
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
Splicevardb		2.0
SpliceAI score (max)		0.080		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: rs137852633; hg19: chr14-55312517;