12-102877461-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PS3_SupportingPVS1PM2PP4PM3

This summary comes from the ClinGen Evidence Repository: The c.441+1G>A variant in PAH is a canonical splice variant in +1 splice site (exon 3/4 junction) in the canonical transcript of PAH, a gene fulfilling the most recent criteria for LOF being a known disease mechanism (PVS1; see PVS1: Recommendations for Interpreting the Loss of Function PVS1 ACMG/AMP Variant Criteria). In addition, the variant has been previously shown by RT-PCR analysis to alter RNA splicing (PS3_Supporting; PMID:8535445). It is ultra-rare (highest observed population frequency 0.00001, with zero homozygotes, in gnomAD Non-Finnish European subpopulation), well under the PAH-specific frequency cutoff of 0.0002 (PM2). It has been found in multiple probands with classic PKU (e.g., PMID:7726156, 8535445, 16256386, 17096675, 20187763, 22112818, 24350308, 23430918, 23764561, 8535445), although BH4 deficiency does not appear to have been formally excluded (PP4), including in trans with the Clinvar-Pathogenic R408W allele (PMID:22112818) (PM3). LINK:https://erepo.genome.network/evrepo/ui/classification/CA229545/MONDO:0009861/006

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

PAH
NM_000277.3 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic reviewed by expert panel P:12O:1

Conservation

PhyloP100: 7.28

Variant links:

Genes affected

PAH (HGNC:8582): (phenylalanine hydroxylase) This gene encodes a member of the biopterin-dependent aromatic amino acid hydroxylase protein family. The encoded phenylalanine hydroxylase enzyme hydroxylates phenylalanine to tyrosine and is the rate-limiting step in phenylalanine catabolism. Deficiency of this enzyme activity results in the autosomal recessive disorder phenylketonuria. [provided by RefSeq, Aug 2017]

PAH links:

LOC124902999 (HGNC:):

LOC124902999 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 14 ACMG points.

PVS1

For more information check the summary or visit ClinGen Evidence Repository.

PS3

For more information check the summary or visit ClinGen Evidence Repository.

PM2

For more information check the summary or visit ClinGen Evidence Repository.

PM3

For more information check the summary or visit ClinGen Evidence Repository.

PP4

For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	Exon rank	MANE	Protein	UniProt
PAH	NM_000277.3 link	c.441+1G>A	splice_donor_variant, intron_variant	Intron 4 of 12	ENST00000553106.6	NP_000268.1	P00439A0A024RBG4
PAH	NM_001354304.2 link	c.441+1G>A	splice_donor_variant, intron_variant	Intron 5 of 13		NP_001341233.1
PAH	XM_017019370.2 link	c.441+1G>A	splice_donor_variant, intron_variant	Intron 4 of 6		XP_016874859.1
LOC124902999	XR_007063428.1 link	n.808-2418C>T	intron_variant	Intron 1 of 2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6 link	c.441+1G>A		splice_donor_variant, intron_variant	Intron 4 of 12	1	NM_000277.3	ENSP00000448059.1		P00439

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152092

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251482

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135914

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1459438

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726224

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152092

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74294

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000805

Hom.:

Bravo

AF:

0.0000113

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:12Other:1

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Phenylketonuria

Pathogenic:8

Jul 18, 2016

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: The PAH c.441+1G>A variant is located at a conserved intronic position, known to affect splicing, with 5/5 splice prediction tools predicting a significant effect on splicing. The variant of interest was observed in the large, broad control population, ExAC, with an allele frequency of 1/121412, which does not exceed the estimated maximal expected allele frequency for a pathogenic PAH variant of 1/126. Multiple publications cite the variant in affected individuals, along with multiple reputable databases/clinical laboratories classify the variant as "pathogenic." Therefore, the variant of interest has been classified as Pathogenic. -

Feb 15, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 4 of the PAH gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or altered protein product. This variant is present in population databases (rs62517166, gnomAD 0.0009%). Disruption of this splice site has been observed in individual(s) with PAH-related conditions (PMID: 7726156, 8535445, 16256386, 17096675, 20187763, 22112818, 24350308). This variant is also known as IVS4+1G>A. ClinVar contains an entry for this variant (Variation ID: 102671). Studies have shown that disruption of this splice site results in skipping of exon 4, and produces a non-functional protein and/or introduces a premature termination codon (PMID: 8535445). For these reasons, this variant has been classified as Pathogenic. -

Apr 01, 2022

Revvity Omics, Revvity

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 02, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Nov 08, 2021

Myriad Genetics, Inc.

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

NM_000277.1(PAH):c.441+1G>A is a canonical splice variant classified as pathogenic in the context of phenylalanine hydroxylase deficiency. Please note c.441+1G>A is associated with classic PKU. c.441+1G>A has been observed in cases with relevant disease (PMID: 32668217). Functional assessments of this variant are not available in the literature. c.441+1G>A has been observed in population frequency databases (gnomAD: NFE 0.001%). In summary, NM_000277.1(PAH):c.441+1G>A is a canonical splice variant in a gene where loss of function is a known mechanism of disease, is predicted to disrupt protein function, and has been observed more frequently in cases with the relevant disease than in healthy populations. Please note: this variant was assessed in the context of healthy population screening. -

Dec 22, 2018

ClinGen PAH Variant Curation Expert Panel

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

The c.441+1G>A variant in PAH is a canonical splice variant in +1 splice site (exon 3/4 junction) in the canonical transcript of PAH, a gene fulfilling the most recent criteria for LOF being a known disease mechanism (PVS1; see PVS1: Recommendations for Interpreting the Loss of Function PVS1 ACMG/AMP Variant Criteria). In addition, the variant has been previously shown by RT-PCR analysis to alter RNA splicing (PS3_Supporting; PMID: 8535445). It is ultra-rare (highest observed population frequency 0.00001, with zero homozygotes, in gnomAD Non-Finnish European subpopulation), well under the PAH-specific frequency cutoff of 0.0002 (PM2). It has been found in multiple probands with classic PKU (e.g., PMID: 7726156, 8535445, 16256386, 17096675, 20187763, 22112818, 24350308, 23430918, 23764561, 8535445), although BH4 deficiency does not appear to have been formally excluded (PP4), including in trans with the Clinvar-Pathogenic R408W allele (PMID: 22112818) (PM3). -

Sep 16, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

not provided

Pathogenic:3Other:1

Jul 17, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Identified in patients with PAH deficiency previously tested at GeneDx and in published literature who harbored a second variant of unknown phase or the second PAH variant was not specifically described (PMID: 17096675, 16256386, 22841515, 23430918, 22112818, 23357515); Canonical splice site variant predicted to result in a null allele in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 22841515, 25087612, 8535445, 23430918, 23357515, 22112818, 16256386, 26600521, 34426522, 32778825, 34738359, 36646061, 32668217, 7726156, 20187763, 24350308, 23764561, 17096675) -

DeBelle Laboratory for Biochemical Genetics, MUHC/MCH RESEARCH INSTITUTE

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Nov 01, 2023

Mayo Clinic Laboratories, Mayo Clinic

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PP4, PM2_moderate, PM3, PS3_moderate, PVS1 -

Nov 06, 2014

Eurofins Ntd Llc (ga)

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Inborn genetic diseases

Pathogenic:1

Jan 12, 2022

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.441+1G>A intronic variant results from a G to A substitution one nucleotide after coding exon 4 of the PAH gene. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. Based on data from gnomAD, the A allele has an overall frequency of <0.01% (1/251482) total alleles studied. The highest observed frequency was <0.01% (1/113762) of European (non-Finnish) alleles. The c.441+1G>A alteration (also described as IVS4+1G>A in the literature) has been reported in multiple patients with phenylalanine hydroxylase deficiency in the compound heterozygous state with various second alterations (Ramus, 1995; Song, 2005; Bonyadi, 2010; Quirk, 2012; Utz, 2012). In addition, several other alterations affecting the same splice site have also been described in affected patients (Hillert, 2020). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. Based on the available evidence, this alteration is classified as pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.27

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.96

FATHMM_MKL

Uncertain

0.94

GERP RS

5.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

0.91

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.91

Position offset: 1

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