Genetic Variant GCH1:c.*1183C>T (chr14-54842834-G-A) – ACMG Classification: Benign (-20 pts)

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBA1

The NM_000161.3(GCH1):c.*1183C>T variant causes a 3 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0221 in 416,152 control chromosomes in the GnomAD database, including 753 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

Frequency

Genomes: 𝑓 0.049 ( 650 hom., cov: 32)

Exomes 𝑓: 0.0067 ( 103 hom. )

Consequence

GCH1
NM_000161.3 3_prime_UTR

Scores

Clinical Significance

Benign criteria provided, multiple submitters, no conflicts B:4

Conservation

PhyloP100: -0.331

Variant links:

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 links:

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ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -20 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.74).

BP6

Variant 14-54842834-G-A is Benign according to our data. Variant chr14-54842834-G-A is described in ClinVar as [Benign]. Clinvar id is 313368.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BA1

GnomAd4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.167 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
GCH1	NM_000161.3 link	c.*1183C>T		3_prime_UTR_variant	Exon 6 of 6	ENST00000491895.7	NP_000152.1	P30793-1A0A024R642

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
GCH1	ENST00000491895 link	c.*1183C>T		3_prime_UTR_variant	Exon 6 of 6	1	NM_000161.3	ENSP00000419045.2		P30793-1

Frequencies

GnomAD3 genomes

AF:

0.0487

AC:

7409

AN:

152096

Hom.:

648

Cov.:

show subpopulations

Gnomad AFR

AF:

0.170

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0165

Gnomad ASJ

AF:

0.000865

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00124

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.0127

Gnomad NFE

AF:

0.000470

Gnomad OTH

AF:

0.0320

GnomAD4 exome

AF:

0.00668

AC:

1763

AN:

263938

Hom.:

103

Cov.:

AF XY:

0.00578

AC XY:

774

AN XY:

133948

show subpopulations

Gnomad4 AFR exome

AF:

0.171

Gnomad4 AMR exome

AF:

0.0138

Gnomad4 ASJ exome

AF:

0.000635

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.000486

Gnomad4 OTH exome

AF:

0.0163

GnomAD4 genome

AF:

0.0487

AC:

7418

AN:

152214

Hom.:

650

Cov.:

AF XY:

0.0474

AC XY:

3529

AN XY:

74420

show subpopulations

Gnomad4 AFR

AF:

0.170

Gnomad4 AMR

AF:

0.0164

Gnomad4 ASJ

AF:

0.000865

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00124

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000470

Gnomad4 OTH

AF:

0.0317

Alfa

AF:

0.0272

Hom.:

Bravo

AF:

0.0555

Asia WGS

AF:

0.0120

AC:

AN:

3478

ClinVar

Significance: Benign

Submissions summary: Benign:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Benign:2

Breakthrough Genomics, Breakthrough Genomics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

Jul 05, 2018

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

GTP cyclohydrolase I deficiency

Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Dystonia 5

Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.74

CADD

Benign

5.1

DANN

Benign

0.85

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over