14-54902402-G-C

Position:

• chr14-54902402-G-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000161.3(GCH1):​c.262C>G​(p.Arg88Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,832 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R88P) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GCH1 NM_000161.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.25

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a chain GTP cyclohydrolase 1 (size 249) in uniprot entity GCH1_HUMAN there are 25 pathogenic changes around while only 3 benign (89%) 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 chrnull-null-null-null is described in UniProt as null.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.987

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
GCH1	NM_000161.3	c.262C>G	p.Arg88Gly	missense_variant	1/6	ENST00000491895.7	NP_000152.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
GCH1	ENST00000491895.7	c.262C>G	p.Arg88Gly	missense_variant	1/6	1	NM_000161.3	ENSP00000419045.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000402 AC: 1 AN: 248876 Hom.: 0 AF XY: 0.00000739 AC XY: 1 AN XY: 135392

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000893

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460832 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 726758

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D;D;.;D;.
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Pathogenic	0.99	.;D;D;.;D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.4	H;H;H;H;H
PrimateAI	Uncertain	0.58	T
PROVEAN	Pathogenic	-6.7	.;D;D;D;D
REVEL	Pathogenic	0.92
Sift	Pathogenic	0.0	.;D;D;D;D
Sift4G	Uncertain	0.0030	D;D;D;D;D
Polyphen		1.0	D;D;D;D;D
Vest4		0.72
MutPred		0.95		Gain of ubiquitination at K93 (P = 0.038);Gain of ubiquitination at K93 (P = 0.038);Gain of ubiquitination at K93 (P = 0.038);Gain of ubiquitination at K93 (P = 0.038);Gain of ubiquitination at K93 (P = 0.038);
MVP		1.0
MPC		2.5
ClinPred		1.0	D
GERP RS		2.5
Varity_R		0.99
gMVP		0.99

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

Publications

LitVar

Other links and lift over

dbSNP: rs104894433; hg19: chr14-55369120;