rs8020798

Variant names:

• chr14-54886650-C-T
• rs8020798
• NM_000161.3:c.343+15671G>A

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 0P and 12B. BP4_Strong BA1

The NM_000161.3(GCH1):​c.343+15671G>A variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.221 in 152,026 control chromosomes in the GnomAD database, including 3,870 homozygotes. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: 𝑓 0.22 (3870 hom., cov: 32)
• Consequence: GCH1 NM_000161.3 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.138
• Publications: 4 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: Benign. The variant received -12 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.86).
• BA1: GnomAd4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.269 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GCH1	NM_000161.3	c.343+15671G>A		intron_variant	Intron 1 of 5	ENST00000491895.7	NP_000152.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GCH1	ENST00000491895.7	c.343+15671G>A		intron_variant	Intron 1 of 5	1	NM_000161.3	ENSP00000419045.2

Frequencies

GnomAD3 genomes AF: 0.221 AC: 33623 AN: 151908 Hom.: 3868 Cov.: 32

Gnomad AFR AF: 0.274

Gnomad AMI AF: 0.363

Gnomad AMR AF: 0.239

Gnomad ASJ AF: 0.139

Gnomad EAS AF: 0.128

Gnomad SAS AF: 0.125

Gnomad FIN AF: 0.251

Gnomad MID AF: 0.104

Gnomad NFE AF: 0.198

Gnomad OTH AF: 0.217

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome AF: 0.221 AC: 33668 AN: 152026 Hom.: 3870 Cov.: 32 AF XY: 0.221 AC XY: 16441 AN XY: 74296

African (AFR) AF: 0.274 AC: 11340 AN: 41446

American (AMR) AF: 0.239 AC: 3654 AN: 15286

Ashkenazi Jewish (ASJ) AF: 0.139 AC: 484 AN: 3470

East Asian (EAS) AF: 0.129 AC: 666 AN: 5164

South Asian (SAS) AF: 0.125 AC: 602 AN: 4810

European-Finnish (FIN) AF: 0.251 AC: 2655 AN: 10578

Middle Eastern (MID) AF: 0.109 AC: 32 AN: 294

European-Non Finnish (NFE) AF: 0.198 AC: 13449 AN: 67956

Other (OTH) AF: 0.216 AC: 455 AN: 2110

Alfa AF: 0.194 Hom.: 856

Bravo AF: 0.222

Asia WGS AF: 0.131 AC: 457 AN: 3478

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.86
CADD	Benign	6.7
DANN	Benign	0.62
PhyloP100		0.14
Mutation Taster		=100/0	polymorphism (auto)

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

Other links and lift over

dbSNP: rs8020798; hg19: chr14-55353368;