14-54902390-G-T

Variant names:

• chr14-54902390-G-T
• rs763294577
• NM_000161.3:c.274C>A
• GCH1 p.Leu92Ile

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1 PP2 PP5 BP4

The NM_000161.3(GCH1):​c.274C>A​(p.Leu92Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000806 in 1,613,066 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L92F) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: GCH1 NM_000161.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• 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: Uncertain_significance. The variant received 3 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
• 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.
• PP5: Variant 14-54902390-G-T is Pathogenic according to our data. Variant chr14-54902390-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 522898.
• BP4: Computational evidence support a benign effect (MetaRNN=0.39850396). . Strength limited to SUPPORTING due to the PP5.

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>A	p.Leu92Ile	missense	Exon 1 of 6	NP_000152.1	P30793-1
	GCH1	NM_001024024.2		c.274C>A	p.Leu92Ile	missense	Exon 1 of 7	NP_001019195.1	P30793-1
	GCH1	NM_001024070.2		c.274C>A	p.Leu92Ile	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>A	p.Leu92Ile	missense	Exon 1 of 6	ENSP00000419045.2	P30793-1
	GCH1	ENST00000395514.5	TSL:1	c.274C>A	p.Leu92Ile	missense	Exon 1 of 7	ENSP00000378890.1	P30793-1
	GCH1	ENST00000543643.6	TSL:1	c.274C>A	p.Leu92Ile	missense	Exon 1 of 7	ENSP00000444011.2	P30793-4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152232 Hom.: 0 Cov.: 33

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: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000803 AC: 2 AN: 248920 AF XY: 0.0000148

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: 0.00

Gnomad NFE exome AF: 0.0000179

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1460834 Hom.: 0 Cov.: 33 AF XY: 0.0000138 AC XY: 10 AN XY: 726758

African (AFR) AF: 0.00 AC: 0 AN: 33462

American (AMR) AF: 0.00 AC: 0 AN: 44708

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26114

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.0000348 AC: 3 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52684

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5748

European-Non Finnish (NFE) AF: 0.00000630 AC: 7 AN: 1111828

Other (OTH) AF: 0.0000331 AC: 2 AN: 60354

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152232 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74374

African (AFR) AF: 0.00 AC: 0 AN: 41476

American (AMR) AF: 0.00 AC: 0 AN: 15290

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5176

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10632

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68036

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.0000330 Hom.: 0

Bravo AF: 0.00000756

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
1	-	-	6-Pyruvoyl-tetrahydrobiopterin synthase deficiency (1)
-	1	-	GTP cyclohydrolase I deficiency;C1851920:Dystonia 5 (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Uncertain	0.086	D
BayesDel_noAF	Benign	-0.10
CADD	Benign	23
DANN	Uncertain	0.98
DEOGEN2	Uncertain	0.74	D
Eigen	Benign	-0.27
Eigen_PC	Benign	-0.16
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.88	D
M_CAP	Pathogenic	0.73	D
MetaRNN	Benign	0.40	T
MetaSVM	Pathogenic	0.96	D
MutationAssessor	Benign	1.3	L
PhyloP100		4.4
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-1.3	N
REVEL	Uncertain	0.47
Sift	Benign	0.10	T
Sift4G	Benign	0.083	T
PromoterAI		0.15	Neutral
Varity_R		0.60
gMVP		0.81
Mutation Taster		=69/31	disease causing (ClinVar)

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;