GCH1 p.Leu92Phe

Variant names:

• chr14-54902390-G-A
• rs763294577
• NM_000161.3:c.274C>T
• GCH1 p.Leu92Phe

Your query was ambiguous. Multiple possible variants found:

• chr14-54902390-G-A
• chr14-54902388-GAG-AAA

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1 PM2 PM5 PP2

The NM_000161.3(GCH1):​c.274C>T​(p.Leu92Phe) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L92I) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: GCH1 NM_000161.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.44
• 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: Orphanet, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, G2P, Ambry Genetics
• GTP cyclohydrolase I deficiency

  Inheritance: AD, SD Classification: DEFINITIVE Submitted by: Illumina, ClinGen
• GTP cyclohydrolase I deficiency with hyperphenylalaninemia

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), Genomics England PanelApp

ENSG00000304580 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a hotspot region, there are 9 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 16 uncertain in NM_000161.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr14-54902390-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 522898.
• 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, GTP cyclohydrolase I deficiency with hyperphenylalaninemia, dystonia 5.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000161.3. 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
	GCH1	NM_000161.3	MANE Select	c.274C>T	p.Leu92Phe	missense	Exon 1 of 6	NP_000152.1	P30793-1
	GCH1	NM_001024024.2		c.274C>T	p.Leu92Phe	missense	Exon 1 of 7	NP_001019195.1	P30793-1
	GCH1	NM_001024070.2		c.274C>T	p.Leu92Phe	missense	Exon 1 of 7	NP_001019241.1	P30793-4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	GCH1	ENST00000491895.7	TSL:1 MANE Select	c.274C>T	p.Leu92Phe	missense	Exon 1 of 6	ENSP00000419045.2	P30793-1
	GCH1	ENST00000395514.5	TSL:1	c.274C>T	p.Leu92Phe	missense	Exon 1 of 7	ENSP00000378890.1	P30793-1
	GCH1	ENST00000543643.6	TSL:1	c.274C>T	p.Leu92Phe	missense	Exon 1 of 7	ENSP00000444011.2	P30793-4

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	1	-	Dystonia 5 (1)
-	1	-	GTP cyclohydrolase I deficiency;C1851920:Dystonia 5 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.49
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.95	D
Eigen	Uncertain	0.24
Eigen_PC	Benign	0.19
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Uncertain	0.62	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.7	H
PhyloP100		4.4
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-3.3	D
REVEL	Pathogenic	0.72
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0030	D
PromoterAI		0.042	Neutral
Varity_R		0.96
gMVP		0.89
Mutation Taster		=19/81	disease causing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs763294577;

hg19: chr14-55369108;