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Prepair 1000+ v1.592 GCH1 Lilian Downie Marked gene: GCH1 as ready
Prepair 1000+ v1.592 GCH1 Lilian Downie Added comment: Comment when marking as ready: Biallelic variants in GCH1 typically result in severe deficiency of GTPCH activity, and result in hyperphenylalaninemia due to secondary PAH deficiency. This can be identified by newborn screening. However, patients with phenotypes that are intermediate between the classic DRD and severe GTPCH deficiency symptoms have been described, such those with severe DRD and additional neurological features but without hyperphenylalaninemia (for review, see Table in Brüggemann et al 2012, PMID 22473768). Because the mechanism of disease in both the monoallelic and biallelic cases is loss of function of GTPCH, and there is a range of GTPCH activity that can cause disease, the decision was made to curate GCH1 for GTPCH deficiency with semi-dominant inheritance. Note that heterozygous parents of biallelic individuals are usually reported as unaffected, although there are some exceptions (Furukawa et al, 1998, PMID 9667588; Bodzioch et al, 2010, PMID 20842687). Reduced penetrance has been reported for individuals with monoallelic GCH1 variants, with penetrance varying according to age and diagnostic criteria. In addition, some variants (e.g. p.Arg184His and p.Lys224Arg) have been reported in monallelic and biallelic individuals. This data was presented to the ClinGen Lumping and Splitting Working Group on November 3, 2020 and there was agreement that GTPCH deficiency should be curated as a semi-dominant trait, including individuals with monoallelic and biallelic GCH1 variants.
Prepair 1000+ v1.592 GCH1 Lilian Downie Gene: gch1 has been classified as Green List (High Evidence).
Prepair 1000+ v1.592 GCH1 Lilian Downie Phenotypes for gene: GCH1 were changed from Dystonia, DOPA-responsive, with or without hyperphenylalaninemia, 128230 (3) to GTP cyclohydrolase I deficiency MONDO:0100184
Prepair 1000+ v1.591 GCH1 Lilian Downie Publications for gene: GCH1 were set to
Prepair 1000+ v1.581 GCH1 Cassandra Muller reviewed gene: GCH1: Rating: GREEN; Mode of pathogenicity: None; Publications: 10737119, 9667588; Phenotypes: Dystonia, DOPA-responsive, with or without hyperphenylalaninemia, 128230 (3); Mode of inheritance: BIALLELIC, autosomal or pseudoautosomal
Prepair 1000+ v1.3 GCH1 Seb Lunke Added phenotypes Dystonia, DOPA-responsive, with or without hyperphenylalaninemia, 128230 (3) for gene: GCH1
Prepair 1000+ v0.0 GCH1 Zornitza Stark gene: GCH1 was added
gene: GCH1 was added to Reproductive Carrier Screen_VCGS. Sources: Mackenzie's Mission,Expert Review Green
Mode of inheritance for gene: GCH1 was set to BIALLELIC, autosomal or pseudoautosomal
Phenotypes for gene: GCH1 were set to Dystonia, DOPA-responsive, with or without hyperphenylalaninemia, 128230 (3)