12-102855322-T-C

Variant names:

• chr12-102855322-T-C
• rs199475632
• NM_000277.3:c.520A>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PP4 PP3 PM3 PM2

This summary comes from the ClinGen Evidence Repository: PAH-specific ACMG/AMP criteria applied: PM2: Not found in any population databases; PP3: All predictors agree--damaging; PM3: Single patient IVS4+5G>T (null) / I174V (Bercovich 2008 PMID 18299955) (PMID:18299955); PP4: Two independent patients (one in Zschocke (PMID 10394930) and one in Bercovich (PMID 18299955) with "PKU". While no specific levels are mentioned, they are followed in clinic and were diagnosed with Phe >120umol/L. BH4 defect WAS NOT excluded in either paper.. 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: (PM2, PP3, PM3, PP4). LINK:https://erepo.genome.network/evrepo/ui/classification/CA229603/MONDO:0009861/006

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: PAH NM_000277.3 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:7 U:1 O:1
• Conservation: PhyloP100: 6.22
• Publications: 3 publications found

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 Gene-Disease associations (from GenCC):

• phenylketonuria

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, ClinGen, Myriad Women’s Health
• classic phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• maternal phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• mild hyperphenylalaninemia

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• mild phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• tetrahydrobiopterin-responsive hyperphenylalaninemia/phenylketonuria

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM3: For more information check the summary or visit ClinGen Evidence Repository.
• PP3: 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	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
PAH	NM_000277.3	c.520A>G	p.Ile174Val	missense_variant	Exon 6 of 13	ENST00000553106.6	NP_000268.1
PAH	NM_001354304.2	c.520A>G	p.Ile174Val	missense_variant	Exon 7 of 14		NP_001341233.1
PAH	XM_017019370.2	c.520A>G	p.Ile174Val	missense_variant	Exon 6 of 7		XP_016874859.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
PAH	ENST00000553106.6	c.520A>G	p.Ile174Val	missense_variant	Exon 6 of 13	1	NM_000277.3	ENSP00000448059.1
PAH	ENST00000549111.5	n.616A>G		non_coding_transcript_exon_variant	Exon 6 of 6	1
PAH	ENST00000307000.7	c.505A>G	p.Ile169Val	missense_variant	Exon 7 of 14	5		ENSP00000303500.2
PAH	ENST00000551988.5	n.541A>G		non_coding_transcript_exon_variant	Exon 5 of 5	3

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152150 Hom.: 0 Cov.: 33

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461790 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727198

African (AFR) AF: 0.0000299 AC: 1 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111942

Other (OTH) AF: 0.0000166 AC: 1 AN: 60392

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152150 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74328

African (AFR) AF: 0.00 AC: 0 AN: 41428

American (AMR) AF: 0.00 AC: 0 AN: 15266

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5190

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68032

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:7 Uncertain:1 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Phenylketonuria Pathogenic:5

Jun 02, 2017

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Aug 16, 2023

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 10, 2018

ClinGen PAH Variant Curation Expert Panel

Significance: Likely pathogenic

Review Status: reviewed by expert panel

Collection Method: curation

PAH-specific ACMG/AMP criteria applied: PM2: Not found in any population databases; PP3: All predictors agree--damaging; PM3: Single patient IVS4+5G>T (null) / I174V (Bercovich 2008 PMID 18299955) (PMID:18299955); PP4: Two independent patients (one in Zschocke (PMID 10394930) and one in Bercovich (PMID 18299955) with "PKU". While no specific levels are mentioned, they are followed in clinic and were diagnosed with Phe >120umol/L. BH4 defect WAS NOT excluded in either paper.. 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: (PM2, PP3, PM3, PP4). -

Aug 05, 2019

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: PAH c.520A>G (p.Ile174Val) results in a conservative amino acid change located in the Aromatic amino acid hydroxylase, C-terminal domain (IPR019774) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251110 control chromosomes. c.520A>G has been reported in the literature in multiple individuals affected with Phenylalanine Hydroxylase Deficiency (mild-PKU/Non-PKU-HPA, Phenylketonuria)(Zschocke_1999, Bercovich_2008, Couce_2013, Yang_2001, Sterl_2013, Reblova_2013). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories (n=1, Likely pathogenic; n=1, VOUS) and one expert panel (Likely pathogenic, ClinGen) have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Based on the evidence outlined above, the variant was classified as pathogenic. -

May 27, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 174 of the PAH protein (p.Ile174Val). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with PAH-related conditions (PMID: 18299955, 22526846, 27121329). ClinVar contains an entry for this variant (Variation ID: 102720). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt PAH protein function with a negative predictive value of 80%. This variant disrupts the p.Ile174 amino acid residue in PAH. Other variant(s) that disrupt this residue have been observed in individuals with PAH-related conditions (PMID: 23842451), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:2 Uncertain:1 Other:1

Jul 13, 2023

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 17924342, 30311390, 23500595, 27121329, 10394930, 27308838, 29997390, 23357515, 22526846, 18299955, 18294361, 11385716, 32668217) -

Apr 01, 2020

CeGaT Center for Human Genetics Tuebingen

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

DeBelle Laboratory for Biochemical Genetics, MUHC/MCH RESEARCH INSTITUTE

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Sep 29, 2015

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.30
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D;T
Eigen	Pathogenic	0.74
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.97	D;D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.92	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.4	M;.
PhyloP100		6.2
PrimateAI	Uncertain	0.49	T
PROVEAN	Benign	-0.91	N;N
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.020	D;D
Polyphen		0.95	P;.
Vest4		0.54
MutPred		0.92		Gain of disorder (P = 0.1171);.;
MVP		0.98
MPC		0.19
ClinPred		0.96	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.65
gMVP		0.77
Mutation Taster		=12/88	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs199475632; hg19: chr12-103249100;