rs5030851
Variant summary
Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PP4_ModeratePP3PM3PS3
This summary comes from the ClinGen Evidence Repository: PAH-specific ACMG/AMP criteria applied: PP3: ; PS3: 2% activity in bioPKU (PAH0309) (PMID:25596310; PMID:17935162); PP4_Moderate: 2 patients with moderate or classical PKU; patients with severe PKU. BH4 deficiency ruled out. (PMID:15503242; PMID:12655553); PM3: IVS4-1G>A (P/LP) (PMID:15503242). In summary this variant meets criteria to be classified as likely pathogenic for phenylketonuria in an autosomal recessive manner based on the ACMG/AMP criteria applied as specified by the PAH Expert Panel: (PP3, PS3, PP4_Moderate, PM3). LINK:https://erepo.genome.network/evrepo/ui/classification/CA220589/MONDO:0009861/006
Frequency
Consequence
NM_000277.3 missense, splice_region
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_pathogenic. Variant got 9 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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PAH | NM_000277.3 | c.842C>T | p.Pro281Leu | missense_variant, splice_region_variant | Exon 7 of 13 | ENST00000553106.6 | NP_000268.1 | |
PAH | NM_001354304.2 | c.842C>T | p.Pro281Leu | missense_variant, splice_region_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.842C>T | p.Pro281Leu | missense_variant, splice_region_variant | Exon 7 of 13 | 1 | NM_000277.3 | ENSP00000448059.1 | ||
PAH | ENST00000307000.7 | c.827C>T | p.Pro276Leu | missense_variant, splice_region_variant | Exon 8 of 14 | 5 | ENSP00000303500.2 | |||
PAH | ENST00000635477.1 | c.2C>T | p.Pro1Leu | missense_variant, splice_region_variant | Exon 1 of 6 | 5 | ENSP00000489230.1 | |||
PAH | ENST00000549247.6 | n.601C>T | splice_region_variant, non_coding_transcript_exon_variant | Exon 1 of 6 | 2 |
Frequencies
GnomAD3 genomes AF: 0.000118 AC: 18AN: 152154Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000103 AC: 26AN: 251254Hom.: 0 AF XY: 0.000103 AC XY: 14AN XY: 135784
GnomAD4 exome AF: 0.000125 AC: 183AN: 1461726Hom.: 0 Cov.: 31 AF XY: 0.000129 AC XY: 94AN XY: 727166
GnomAD4 genome AF: 0.000118 AC: 18AN: 152154Hom.: 0 Cov.: 32 AF XY: 0.000121 AC XY: 9AN XY: 74328
ClinVar
Submissions by phenotype
Phenylketonuria Pathogenic:19Other:1
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PS3, PM3_Strong, PP3 -
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This variant was identified as compound heterozygous. -
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The p.Pro281Leu variant in PAH was first reported in patients with classic PKU by Okano et al., (Okano 1991, Okano 1991) and has been reported in numerous patients with PKU since then (Zurfluh 2008, Danecka 2015). In vitro functional studies provide evidence that the p.Pro281Leu variant impacts protein function (Okano 1991, Zurfluh 2008, Danecka 2015, Ellingsen 1999, Reblova 2015, Shi 2012). This variant has been identified in 0.018% (12/66740) of Euroepan chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; rs5030851). Although this variant has been seen in the general population, its frequency is low enough to be consistent with a recessive carrier frequency. In summary, this variant meets our criteria to be classified as pathogenic for phenylketonuria in an autosomal recessive manner. -
Variant summary: The PAH c.842C>T (p.Pro281Leu) variant involves the alteration of a conserved nucleotide. 5/5 in silico tools predict a damaging outcome for this variant, which was confirmed by at least one in vitro study showing the activity of PAH p.P281L was <1% of wild-type PAH activity (Kayaalp_1997). This variant was found in 12/121404 control chromosomes at a frequency of 0.0000988, which does not exceed the estimated maximal expected allele frequency of a pathogenic PAH variant (0.0079057). This variant has been reported in numerous patients with classic PKU. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as pathogenic. Taken together, this variant is classified as pathogenic. -
PAH-specific ACMG/AMP criteria applied: PP3: ; PS3: 2% activity in bioPKU (PAH0309) (PMID:25596310; PMID:17935162); PP4_Moderate: 2 patients with moderate or classical PKU; patients with severe PKU. BH4 deficiency ruled out. (PMID:15503242; PMID:12655553); PM3: IVS4-1G>A (P/LP) (PMID:15503242). In summary this variant meets criteria to be classified as likely pathogenic for phenylketonuria in an autosomal recessive manner based on the ACMG/AMP criteria applied as specified by the PAH Expert Panel: (PP3, PS3, PP4_Moderate, PM3). -
NM_000277.1(PAH):c.842C>T(P281L) is classified as pathogenic in the context of phenylalanine hydroxylase deficiency. Sources cited for classification include the following: PMID 22513348, 22526846, 19394257, 15503242, 20920871, 20187763, 22763404, 18299955, 17935162 and 10471838. Classification of NM_000277.1(PAH):c.842C>T(P281L) is based on the following criteria: This is a well-established pathogenic variant in the literature that has been observed more frequently in patients with clinical diagnoses than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -
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This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 281 of the PAH protein (p.Pro281Leu). This variant is present in population databases (rs5030851, gnomAD 0.02%). This missense change has been observed in individual(s) with PAH-related conditions (PMID: 1672294, 21871829, 25596310; internal data). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 589). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects PAH function (PMID: 1672294, 17935162, 21953985). For these reasons, this variant has been classified as Pathogenic. -
Same nucleotide change resulting in same amino acid change has been previously reported as pathogenic/likely pathogenic with strong evidence (ClinVar ID: VCV000000589, PMID:1672294, PS1_S). A different missense change at the same codon has been reported to be associated with PAH related disorder (ClinVar ID: VCV000092749, PMID:12409276,10598814,15171997, PM5_P). In silico tool predictions suggest damaging effect of the variant on gene or gene product (REVEL: 0.983, 3CNET: 0.998, PP3_P). A missense variant is a common mechanism associated with Classic phenylketonuria (PP2_P). It is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.000103, PM2_M). Therefore, this variant is classified as likely pathogenic according to the recommendation of ACMG/AMP guideline. -
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The PAH c.842C>T (p.P281L) variant is located at an intron/exon boundary, and this variant has been reported as pathogenic in individuals with phenylketonuria. This variant was also shown to abolish the function of the phenylalanine hydroxylase enzyme in vitro (PMID: 1672290; 9634518; 10234516; 17935162). -
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This sequence variant is a single nucleotide substitution (C>T) at position 842 of the coding sequence of the PAH gene that results in a proline to leucine amino acid change at residue 281 of the phenylalanine hydroxylase protein. This residue falls in the catalytic domain of the protein which is important for the binding of iron, cofactor, and substrate (PMID: 23457044). This is a previously reported variant (ClinVar 589) that has been classified as likely pathogenic by an expert panel (ClinGen SCV000852092.4). This variant has been observed in individuals affected by phenylketonuria and hyperphenylalaninemia (PMID: 17935162, 15503242, 12655553, 24368688). This variant is present in 201 of 1613880 alleles (0.012%) in the gnomAD v4.0.0 population dataset. Multiple bioinformatic tools predict that this amino acid change would be damaging, and the Pro281 residue at this position is highly conserved across the vertebrate species examined. Studies examining the functional consequence of this variant demonstrate significantly impaired enzymatic activity (PMID: 25596310, 17935162). Based upon the evidence, we consider this variant to be likely pathogenic. ACMG Criteria: PM3, PP3, PP4, PS3 -
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not provided Pathogenic:5Other:1
In the literature, this variant has been reported as homozygous or compound heterozygous with other pathogenic PAH variants in many individuals with PAH-related diseases (PMIDs: 30747360 (2019), 29749107 (2018), 25596310 (2015), 21871829 (2011), 20082265 (2010), 18294361 (2008), and 1672294 (1991)). An in vitro study indicated that the homozygous c.842C>T (p.Pro281Leu) variant could generate a full length splicing product and a shorter splicing product without exon 8. The full length product has minimal enzyme activity and the shorter product causes the premature termination of the PAH protein (PMID 10471838 (1999)). Multiple other experimental studies have also confirmed that this variant results in diminished enzyme activity and protein expression (PMID: 25596310 (2015), 21953985 (2012), 17935162 (2008), 11161839 (2001), and 1672294 (1991)). This pathogenic variant is located in the catalytic domain of the PAH protein and is associated with classic PKU (PMID 20082265 (2010)). -
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Associated with very low (0-1%) residual phenylalanine hydroxylase enzyme activity and is considered a severe PAH variant as individuals homozygous for this variant have been reported with classic phenylketonuria (Okano et al., 1991; Rivera et al., 2011; Shi et al., 2012; Danecka et al., 2015); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Reported to not be responsive to tetrahydrobiopterin (BH4) therapy (Zurflh et al., 2008); This variant is associated with the following publications: (PMID: 33101986, 31589614, 32853555, 30275481, 30747360, 31355225, 30648773, 30963030, 30159272, 12501224, 24296287, 21871829, 29288420, 1672294, 29499199, 2014036, 28676969, 19194782, 22513348, 8889590, 1672290, 25750018, 17935162, 1481864, 21953985, 25596310, 25087612, 22975760, 21228398, 10471838) -
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PAH: PM3:Very Strong, PM1, PM2, PM5, PP4:Moderate, PP3, PS3:Supporting -
PP3, PP4_moderate, PM2_moderate, PM5, PS3 -
PAH-related disorder Pathogenic:1
The PAH c.842C>T variant is predicted to result in the amino acid substitution p.Pro281Leu. This variant is a recurrent variant that has been documented as causative for phenylalanine hydroxylase deficiency and has been associated with classical phenylketonuria (PKU) (e.g., Okano et al. 1991. PubMed ID: 2014036; Ellingsen et al. 1999, PubMed ID: 10471838; Trunzo et al. 2014, PubMed ID: 24296287; Hillert et al. 2020. PubMed ID: 32668217). The p.Pro281 amino acid resides in the cofactor binding site (CBR) region of the PAH enzyme, and the p.Pro281Leu substitution has been reported to reduce enzyme activity to ~1% of control and result in a mutant PAH protein that is non-responsive to BH4 (Zurflüh et al. 2008. PubMed ID: 17935162). This variant is classified as pathogenic or likely pathogenic by multiple outside laboratories, as well as the ClinGen PAH Variant Curation Expert Panel (https://www.ncbi.nlm.nih.gov/clinvar/variation/589/). This variant is interpreted as pathogenic. -
Inborn genetic diseases Pathogenic:1
The c.842C>T (p.P281L) alteration is located in exon 7 (coding exon 7) of the PAH gene. This alteration results from a C to T substitution at nucleotide position 842, causing the proline (P) at amino acid position 281 to be replaced by a leucine (L). Based on data from the Genome Aggregation Database (gnomAD) database, the PAH c.842C>T alteration was observed in 0.01% (29/282652) of total alleles studied, with a frequency of 0.02% (26/128978) in the European (non-Finnish) subpopulation. This mutation has been identified in numerous individuals with phenylalanine hydroxylase (PAH) deficiency (Okano, 1991; Shi, 2012; Gundorova, 2019) Activity and protein levels were approximately 1% when this variant was expressed n COS cells (Shi, 2012) The p.P281L alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at