12-102877457-C-A
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: The c.441+5G>T variant in PAH has been reported on >17 PKU alleles (BH4 deficiency excluded). (PP4_Moderate; PMID:17935162; PMID:23514811). This variant has an extremely low allele frequency (0.00002886) in gnomAD (PM2; http://gnomad.broadinstitute.org). This variant has 0% enzyme activity (PS3; http://www.biopku.org). This variant was detected in trans with IVS10-11g>a and p.V388M (Pathogenic in ClinVar) (PM3_Strong; PMID:23514811). Computational prediction tools and conservation analysis suggest that the c.441+5G>T variant may impact the protein (PP3). In summary, this variant meets criteria to be classified as pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PP4_Moderate, PS3, PM3_Strong LINK:https://erepo.genome.network/evrepo/ui/classification/CA273112/MONDO:0009861/006
Frequency
Consequence
NM_000277.3 splice_region, intron
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.441+5G>T | splice_region_variant, intron_variant | Intron 4 of 12 | ENST00000553106.6 | NP_000268.1 | ||
PAH | NM_001354304.2 | c.441+5G>T | splice_region_variant, intron_variant | Intron 5 of 13 | NP_001341233.1 | |||
PAH | XM_017019370.2 | c.441+5G>T | splice_region_variant, intron_variant | Intron 4 of 6 | XP_016874859.1 | |||
LOC124902999 | XR_007063428.1 | n.808-2422C>A | intron_variant | Intron 1 of 2 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152116Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000318 AC: 8AN: 251488Hom.: 0 AF XY: 0.0000221 AC XY: 3AN XY: 135918
GnomAD4 exome AF: 0.0000233 AC: 34AN: 1458196Hom.: 0 Cov.: 31 AF XY: 0.0000248 AC XY: 18AN XY: 725660
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152116Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74308
ClinVar
Submissions by phenotype
Phenylketonuria Pathogenic:11
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The variant has been reported multiple times as an established pathogenic/likely pathogenic variant (ClinVar ID: VCV000092742). Functional studies provide strong evidence of the variant having a damaging effect on the gene or gene product (BioPKU, PS3_S). In silico prediction tools predicted that this variant influenced pre-mRNA splicing, resulting in aberrant splicing (SPLICEAI: 0.91>=0.8, PP3_P). It is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.000032, PM2_M). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -
The c.441+5G>T variant in PAH has been reported in at least 20 individuals with phenylalanine hydroxylase deficiency including at least 12 compound heterozygotes (Zurflüh 2008 PMID: 17935162, Bueno 2013 PMID: 23514811), several of whom presented with classical phenylketonuria (PKU). It has also been identified in 0.0065% (1/15282) of Latino chromosomes by gnomAD (http://gnomad.broadinstitute.org). This variant has been reported in ClinVar as pathogenic by the ClinGen PAH Variant Curation Expert Panel using the . ACMG-AMP criteria specific for phenylalanine hydroxylase variants (Zastrow 2018 PMID: 30311390) and is curated in the FDA-recognized human genetic variant database (Variation ID 102784). Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. In vitro functional studies provide some evidence that this variant impacts protein function and decreases PAH activity to 0% (Bueno 2013 PMID: 23514811); however, these types of assays may not accurately represent biological function. In summary, this variant meets criteria to be classified as pathogenic for autosomal recessive phenylalanine hydroxylase deficiency. ACMG/AMP Criteria applied: PM2_Supporting, PP3, PP4_Moderate, PM3_VeryStrong, PS3 -
The c.441+5G>T variant in PAH has been reported on >17 PKU alleles (BH4 deficiency excluded). (PP4_Moderate; PMID: 17935162; PMID: 23514811). This variant has an extremely low allele frequency (0.00002886) in gnomAD (PM2; http://gnomad.broadinstitute.org). This variant has 0% enzyme activity (PS3; http://www.biopku.org). This variant was detected in trans with IVS10-11g>a and p.V388M (Pathogenic in ClinVar) (PM3_Strong; PMID: 23514811). Computational prediction tools and conservation analysis suggest that the c.441+5G>T variant may impact the protein (PP3). In summary, this variant meets criteria to be classified as pathogenic for PAH. PAH-specific ACMG/AMP criteria applied: PP4_Moderate, PS3, PM3_Strong -
Variant summary: The PAH c.441+5G>T variant involves the alteration of a conserved intronic nucleotide with 4/5 splice prediction tools predicting a significant impact on normal splicing. The variant of interest was observed in the large, broad control population, ExAC, with an allele frequency of 5/121412 (1/24271), which does not exceed the estimated maximal expected allele frequency for a pathogenic PAH variant of 1/126 (0.0079057). Multiple publications cite the variant in affected individuals who are homozygous and compound heterozygous, along with multiple databases/clinical diagnostic laboratories citing the variant as "pathogenic." Therefore, the variant of interest has been classified as Pathogenic. -
This sequence change falls in intron 4 of the PAH gene. It does not directly change the encoded amino acid sequence of the PAH protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs62507321, gnomAD 0.01%). This variant has been observed in individual(s) with phenylketonuria or hyperphenylalaninemia (PMID: 9429153, 17502162, 23514811, 23764561, 24296287, 24368688, 24941924, 25596310, 26666653). 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: 92742). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -
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not provided Pathogenic:4Other:1
PAH: PM3:Very Strong, PM2, PP4:Moderate, PP3 -
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Many individuals with c.441+5 G>T and another PAH variant were not found to be responsive to tetrahydrobiopterin (BH4), but data are still unclear (Zurfluh et al., 2008; Jeannesson-Thivisol et al., 2015); Not observed at a significant frequency in large population cohorts (gnomAD); Intronic +5 splice site variant in a gene for which loss of function is a known mechanism of disease, and splice predictors support a deleterious effect; This variant is associated with the following publications: (PMID: 31355225, 24296287, 28676969, 9429153, 34426522, 31589614, 33101986, 32778825, 33465300, 33375644, 24941924, 23514811, 25087612, 26481238, 27121329, 26666653) -
PP3, PM2_moderate, PM3_strong, PS3 -
PAH-related disorder Pathogenic:1
The PAH c.441+5G>T variant is predicted to interfere with splicing. This variant, which lies near the junction of exon 4 and intron 4 and is predicted to disrupt splicing, has been reported as causative in either the homozygous or compound heterozygous state for phenylalanine hydroxylase deficiency (see for example Zekanowski et al. 1997. PubMed ID: 9429153; Bueno et al. 2013. PubMed ID: 23514811; Trunzo et al. 2013. PubMed ID: 24296287; Table S3 in Hillert et al. 2020. PubMed ID: 32668217). Other variants within the same splice site region (e.g., c.441+1G>A,c.441+2T>G, c.441+3G>C, c.441+6T>A) have been reported with a second PAH variant in individuals with phenylalanine hydroxylase deficiency (see for example Table S3 in Hillert et al. 2020. PubMed ID: 32668217). This variant is reported in 0.011% of alleles in individuals of Latino descent in gnomAD. This variant has been classified as pathogenic by the ClinGen PAH Variant Curation Expert Panel as well as multiple other submitters to ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/92742/). Taken together, this variant is interpreted as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at