rs76687508
Variant summary
Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM2PP4_ModeratePP3PS3PM3_Strong
This summary comes from the ClinGen Evidence Repository: PAH-specific ACMG/AMP criteria applied: PM2: Extremely low frequency in ExAC (0.00014) and gnomAD (0.0001301); PP3: Deleterious effect predicted in SIFT, PolyPhen2, MutationTaster; PP4_Moderate: Seen in multiple PKU patients. BH4 deficiency excluded in 2 patients. Upgraded per ClinGen Metabolic Workgroup. (PMID:8222245; PMID:11142755); PM3_Strong: R241C seen once in trans with R413P, and once with R243Q, both pathogenic. Upgraded per ClinGen SVI Workgroup. (PMID:11142755); PS3: In vitro PAH R241C mutant was found to have 25% PAH activity of normal. In vivo phenylalanine breath test measured a decreased level in R241C homozygote. (PMID:15319459; PMID:7915167). In summary this variant meets criteria to be classified as pathogenic for phenylketonuria in an autosomal recessive manner based on the ACMG/AMP criteria applied as specified by the PAH Expert Panel: (PM2, PP3, PP4_Moderate, PM3_Strong, PS3). LINK:https://erepo.genome.network/evrepo/ui/classification/CA273357/MONDO:0009861/006
Frequency
Consequence
NM_000277.3 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 13 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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PAH | NM_000277.3 | c.721C>T | p.Arg241Cys | missense_variant | Exon 7 of 13 | ENST00000553106.6 | NP_000268.1 | |
PAH | NM_001354304.2 | c.721C>T | p.Arg241Cys | missense_variant | Exon 8 of 14 | NP_001341233.1 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
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PAH | ENST00000553106.6 | c.721C>T | p.Arg241Cys | missense_variant | Exon 7 of 13 | 1 | NM_000277.3 | ENSP00000448059.1 | ||
PAH | ENST00000307000.7 | c.706C>T | p.Arg236Cys | missense_variant | Exon 8 of 14 | 5 | ENSP00000303500.2 | |||
PAH | ENST00000549247.6 | n.480C>T | non_coding_transcript_exon_variant | Exon 1 of 6 | 2 | |||||
PAH | ENST00000635477.1 | c.-120C>T | upstream_gene_variant | 5 | ENSP00000489230.1 |
Frequencies
GnomAD3 genomes AF: 0.0000921 AC: 14AN: 152082Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000143 AC: 36AN: 250956Hom.: 0 AF XY: 0.000147 AC XY: 20AN XY: 135644
GnomAD4 exome AF: 0.0000445 AC: 65AN: 1461820Hom.: 0 Cov.: 32 AF XY: 0.0000440 AC XY: 32AN XY: 727214
GnomAD4 genome AF: 0.0000920 AC: 14AN: 152200Hom.: 0 Cov.: 32 AF XY: 0.0000941 AC XY: 7AN XY: 74414
ClinVar
Submissions by phenotype
Phenylketonuria Pathogenic:13
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PM3_VeryStrong+PP4_Moderate+PS3 -
This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 241 of the PAH protein (p.Arg241Cys). This variant is present in population databases (rs76687508, gnomAD 0.1%). This missense change has been observed in individuals with PAH-related diseases (PMID: 8222245, 11486900, 14681498, 18985011, 19915519, 24368688, 26322415; internal data). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 102803). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt PAH protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects PAH function (PMID: 16253218). For these reasons, this variant has been classified as Pathogenic. -
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The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.014%). Missense changes are a common disease-causing mechanism. Functional studies provide strong evidence of the variant having a damaging effect on the gene or gene product (PMID: 15319459 , 7915167). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.86; 3Cnet: 0.99). The variant has been reported to be in trans with a pathogenic variant as either compound heterozygous or homozygous in at least 2 similarly affected unrelated individuals (PMID: 11142755). A different missense change at the same codon (p.Arg241His) has been reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000102804). Therefore, this variant is classified as Pathogenic according to the recommendation of ACMG/AMP guideline. -
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PAH-specific ACMG/AMP criteria applied: PM2: Extremely low frequency in ExAC (0.00014) and gnomAD (0.0001301); PP3: Deleterious effect predicted in SIFT, PolyPhen2, MutationTaster; PP4_Moderate: Seen in multiple PKU patients. BH4 deficiency excluded in 2 patients. Upgraded per ClinGen Metabolic Workgroup. (PMID:8222245; PMID:11142755); PM3_Strong: R241C seen once in trans with R413P, and once with R243Q, both pathogenic. Upgraded per ClinGen SVI Workgroup. (PMID:11142755); PS3: In vitro PAH R241C mutant was found to have 25% PAH activity of normal. In vivo phenylalanine breath test measured a decreased level in R241C homozygote. (PMID:15319459; PMID:7915167). In summary this variant meets criteria to be classified as pathogenic for phenylketonuria in an autosomal recessive manner based on the ACMG/AMP criteria applied as specified by the PAH Expert Panel: (PM2, PP3, PP4_Moderate, PM3_Strong, PS3). -
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Variant summary: The c.721C>T variant affects a conserved nucleotide, resulting in amino acid change from Arg to Cys located at catalytic domain of the protein. 5/5 in-silico tools predict this variant to be damaging. This variant was found in 17/120962 control chromosomes in the heterozygous state from the large and broad populations of ExAC at a frequency of 0.0001405, which does not exceed the maximal expected frequency of a pathogenic allele (0.0079057) in this gene. This variant is found in several patients with phenylketonuria with concordant recessive genotypes and is reported to be the most common mild pathogenic variant in the Taiwanese population. Functional studies are concordant with impairment of enzymatic activity. Multiple clinical laboratories have classified this variant as pathogenic. Taken together, this variant has been classified as Pathogenic. -
not provided Pathogenic:5Other:1
PAH: PM3:Very Strong, PM2, PM5, PP3, PP4, PS3:Supporting -
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Associated with mild hyperphenylalaninemia or mild phenylketonuria (PKU), although it has also been reported in an individual with classic PKU (Chien et al., 2004; Lee et al., 2008; Liang et al., 2014); R241C is associated with reduced residual PAH enzyme activity (Liang et al., 2014); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 11486900, 25750018, 9860305, 18985011, 9634518, 8222245, 14722928, 27264808, 29499199, 29317692, 11243094, 29961769, 30678510, 30747360, 30275481, 34426522, 33677757, 32668217, 32778825, 30037505, 17935162, 24401910, 31053953) -
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PAH-related disorder Pathogenic:1
The PAH c.721C>T variant is predicted to result in the amino acid substitution p.Arg241Cys. This variant has been reported in both the homozygous and compound heterozygous states in affected individuals and has been associated with mild hyperphenylalaninemia and mild phenylketonuria (e.g., Okano et al. 1994, PubMed ID: 7915167; Spaapen et al. 2001. PubMed ID: 11486900; Liang et al. 2014. PubMed ID: 24401910). This is a common pathogenic variant in the PAH gene, accounting for 1.5% of ~16,000 alleles documented in the PAHvdb (Hillert et al. 2020. PubMed ID: 32668217) and it is thought to be a founder variant in the Taiwanese population (Liang et al. 2014. PubMed ID: 24401910). The p.Arg241Cys amino acid change has been reported to decrease the activity of the PAH protein to roughly 25-50% of wild-type (Zurflüh et al. 2008. PubMed ID: 17935162; Liang et al. 2014. PubMed ID: 24401910). This variant is classified as pathogenic by multiple outside laboratories and the ClinGen PAH Variant Curation Expert Panel (https://www.ncbi.nlm.nih.gov/clinvar/variation/102803). This variant is interpreted as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at